Materiały źródłowe

• #1 Haemophilus Influenzae Infections: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/964317-overview

  Haemophilus influenzae is a small (1 m X 0.3 m), pleomorphic, gram-negative coccobacillus. Some strains of H influenzae possess a polysaccharide capsule. The most virulent strain is H influenzae type b (Hib), with its polyribosyl ribitol phosphate (PRP) capsule. It accounts for more than 95% of H influenzae invasive diseases in children and half of invasive diseases in adults, including bacteremia, meningitis, cellulitis, epiglottitis, septic arthritis, pneumonia, and empyema. […] The antiphagocytic nature of the Hib capsule and the absence of the anticapsular antibody lead to increasing bacterial proliferation. When the bacterial concentration exceeds a critical level, it can disseminate to various sites, including meninges, subcutaneous tissue, joints, pleura, pericardia, and lungs. […] The Hib conjugate vaccine induces protection by inducing antibodies against the PRP capsule. The Hib conjugate vaccine does not provide protection against NTHi strains. Since the widespread use of the Hib conjugate vaccine, NTHi has become a more common pathogen.

• #2 Haemophilus influenzae – Wikipedia

  https://en.wikipedia.org/wiki/Haemophilus_influenzae

  H. influenzaeis responsible for a wide range of localized and invasive infections, typically in infants and children, including pneumonia, meningitis, or bloodstream infections. […] The pathogenesis of H. influenzaeinfections is not completely understood, although the presence of the polyribosyl ribitol phosphate (PRP) capsule in encapsulated type b (Hib), a serotype causing conditions such as epiglottitis, is known to be a major factor in virulence. […] Their capsule allows them to resist phagocytosis and complement-mediated lysis in the nonimmune host. […] The unencapsulated strains are almost always less invasive; however, they can produce an inflammatory response in humans, which can lead to many symptoms. […] H. influenzaecan cause respiratory tract infections including pneumonia, otitis media, epiglottitis (swelling in the throat), eye infections and bloodstream infection, meningitis.

• #3 Haemophilus influenzae infection – wikidoc

  https://www.wikidoc.org/index.php/Haemophilus_influenzae_infection

  H. influenzae is a gram-negative, cocco-bacillary, facultatively anaerobic pathogenic bacterium that can cause infections in people of all ages ranging from mild, such as an ear infection, to severe, such as a bloodstream infection. […] The pathogenesis of H.influenzae infections can be described as follows: […] The capsule of H influenza plays a key role in the pathogenesis of the all the capsulated H influenza infections. […] The antiphagocytic nature of the Hib capsule makes it resistant to natural host phagocytic defense mechanisms and facilitating bacterial proliferation. […] After proliferation, the bacterial load disseminates to various sites, including meninges, subcutaneous tissue, joints, pleura, pericardium, and lungs triggering an inflammatory response and subsequently activating the complement system.

• #4 Haemophilus Species – Medical Microbiology – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK8458/

  Type b Haemophilus influenzae colonizes the nasopharynx, and may penetrate the epithelium and capillary endothelium to cause bacteremia. Meningitis may result from direct spread via lymphatic drainage or from hematogenous spread. Nontypable H influenzae colonizes the nasopharynx and, to a lesser extent, the trachea and bronchi and may infect mucosa damaged by viral disease or cigarette smoking. Lipooligosaccharide is largely responsible for inflammation; exotoxins do not play a role. […] The pathogenesis of H influenzae infections is not completely understood, but the presence of the type b polysaccharide capsule is a major factor in virulence. Encapsulated organisms can penetrate the epithelium of the nasopharynx and invade blood capillaries directly. Nontypable strains are less invasive, but they, as well as typable strains, induce an inflammatory response that causes disease; production of exotoxins is not thought to play a role in pathogenicity. Nontypable H influenzae strains colonize the nasopharynx of most normal individuals, but type b H influenzae strains are found in only 1 to 2 percent of normal children. Outbreaks of type b infection occur, especially in nurseries and child care centers; prophylactic administration of antibiotics may be used. Vaccination with type b polysaccharide appears to be effective in preventing infection, and vaccines are now available for routine use.

• #5 Haemophilus influenzae – Wikipedia

  https://en.wikipedia.org/wiki/Haemophilus_influenzae

  H. influenzaeis responsible for a wide range of localized and invasive infections, typically in infants and children, including pneumonia, meningitis, or bloodstream infections. […] The pathogenesis of H. influenzaeinfections is not completely understood, although the presence of the polyribosyl ribitol phosphate (PRP) capsule in encapsulated type b (Hib), a serotype causing conditions such as epiglottitis, is known to be a major factor in virulence. […] Their capsule allows them to resist phagocytosis and complement-mediated lysis in the nonimmune host. […] The unencapsulated strains are almost always less invasive; however, they can produce an inflammatory response in humans, which can lead to many symptoms. […] H. influenzaecan cause respiratory tract infections including pneumonia, otitis media, epiglottitis (swelling in the throat), eye infections and bloodstream infection, meningitis.

• #6 Haemophilus Influenzae Infections: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/964317-overview

  Haemophilus influenzae is a small (1 m X 0.3 m), pleomorphic, gram-negative coccobacillus. Some strains of H influenzae possess a polysaccharide capsule. The most virulent strain is H influenzae type b (Hib), with its polyribosyl ribitol phosphate (PRP) capsule. It accounts for more than 95% of H influenzae invasive diseases in children and half of invasive diseases in adults, including bacteremia, meningitis, cellulitis, epiglottitis, septic arthritis, pneumonia, and empyema. […] The antiphagocytic nature of the Hib capsule and the absence of the anticapsular antibody lead to increasing bacterial proliferation. When the bacterial concentration exceeds a critical level, it can disseminate to various sites, including meninges, subcutaneous tissue, joints, pleura, pericardia, and lungs. […] The Hib conjugate vaccine induces protection by inducing antibodies against the PRP capsule. The Hib conjugate vaccine does not provide protection against NTHi strains. Since the widespread use of the Hib conjugate vaccine, NTHi has become a more common pathogen.

• #7 Disease information about Invasive Haemophilus influenzae disease

  https://www.ecdc.europa.eu/en/invasive-haemophilus-influenzae-disease/facts

  Haemophilus influenzae serotype b (Hib) is the most common cause of bacterial meningitis in children aged two months to five years, in those countries where suitable vaccination programmes are not in place. […] Haemophilus influenzae type b is an encapsulated, immotile and non-spore forming Gram-negative coccobacillus. […] Serotype b (Hib) has a polyribosyl ribitol phosphate (PRP) polysaccharide capsule that is a major virulence factor. […] The PRP capsule protects the organism from phagocytosis in the absence of anticapsular antibodies and facilitates penetration to the blood stream and the cerebrospinal fluid. […] Haemophilus influenzae type b causes pneumonia, septicaemia, meningitis, epiglottitis, septic arthritis, cellulitis, otitis media, and purulent pericarditis, as well as less common invasive infections such as endocarditis, osteomyelitis, and peritonitis.

• #8 Haemophilus influenzae: Infectious substances pathogen safety data sheet – Canada.ca

  https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/haemophilus-influenzae-type-b.html

  Haemophilus influenzae is differentiated into six capsular types (a to f) according to its capsular polysaccharide structure. […] The most virulent serotype is H. influenzae type b (Hib), and its capsule, composed of polyribosyl ribitol phosphate (PRP), is the predominant virulence determinant. […] The capsule confers antiphagocytic properties to the bacteria and increases proliferation. […] Proteins such as Haemophilus surface fibrils (Hsf) and protein H are present on encapsulated strains and aid in adherence to the host cells. […] Outer-membrane proteins contribute to virulence and some are thought to be involved in invasion of mucosal epithelium. […] Pili mediate bacterial adherence to mucosal surfaces and facilitate respiratory tract colonization. […] H. influenzae secretes immunoglobulin A1 (IgA1) which acts to inactivate human IgA1, thus evading host immune function and promoting colonization. […] The lipopolysaccharide (LPS) is an important structural component, and is also involved in colonization and resistance to host immune response.

• #9 Haemophilus influenzae – Wikipedia

  https://en.wikipedia.org/wiki/Haemophilus_influenzae

  H. influenzaeis responsible for a wide range of localized and invasive infections, typically in infants and children, including pneumonia, meningitis, or bloodstream infections. […] The pathogenesis of H. influenzaeinfections is not completely understood, although the presence of the polyribosyl ribitol phosphate (PRP) capsule in encapsulated type b (Hib), a serotype causing conditions such as epiglottitis, is known to be a major factor in virulence. […] Their capsule allows them to resist phagocytosis and complement-mediated lysis in the nonimmune host. […] The unencapsulated strains are almost always less invasive; however, they can produce an inflammatory response in humans, which can lead to many symptoms. […] H. influenzaecan cause respiratory tract infections including pneumonia, otitis media, epiglottitis (swelling in the throat), eye infections and bloodstream infection, meningitis.

• #10 Haemophilus Meningitis: Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/1164916-overview

  The polysaccharide capsule of these organisms not only confers virulence and invasiveness but also provides resistance to opsonization and complement-mediated bactericidal activities and inhibits neutrophil phagocytosis. […] The development of resistance to Hib infection appears to be due to gradual acquisition of antibodies directed at capsular determinants of Hib and possibly to other aspects of immune system maturation.

• #11 Disease information about Invasive Haemophilus influenzae disease

  https://www.ecdc.europa.eu/en/invasive-haemophilus-influenzae-disease/facts

  Haemophilus influenzae serotype b (Hib) is the most common cause of bacterial meningitis in children aged two months to five years, in those countries where suitable vaccination programmes are not in place. […] Haemophilus influenzae type b is an encapsulated, immotile and non-spore forming Gram-negative coccobacillus. […] Serotype b (Hib) has a polyribosyl ribitol phosphate (PRP) polysaccharide capsule that is a major virulence factor. […] The PRP capsule protects the organism from phagocytosis in the absence of anticapsular antibodies and facilitates penetration to the blood stream and the cerebrospinal fluid. […] Haemophilus influenzae type b causes pneumonia, septicaemia, meningitis, epiglottitis, septic arthritis, cellulitis, otitis media, and purulent pericarditis, as well as less common invasive infections such as endocarditis, osteomyelitis, and peritonitis.

• #12 Haemophilus influenzae: Infectious substances pathogen safety data sheet – Canada.ca

  https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/haemophilus-influenzae-type-b.html

  Haemophilus influenzae is differentiated into six capsular types (a to f) according to its capsular polysaccharide structure. […] The most virulent serotype is H. influenzae type b (Hib), and its capsule, composed of polyribosyl ribitol phosphate (PRP), is the predominant virulence determinant. […] The capsule confers antiphagocytic properties to the bacteria and increases proliferation. […] Proteins such as Haemophilus surface fibrils (Hsf) and protein H are present on encapsulated strains and aid in adherence to the host cells. […] Outer-membrane proteins contribute to virulence and some are thought to be involved in invasion of mucosal epithelium. […] Pili mediate bacterial adherence to mucosal surfaces and facilitate respiratory tract colonization. […] H. influenzae secretes immunoglobulin A1 (IgA1) which acts to inactivate human IgA1, thus evading host immune function and promoting colonization. […] The lipopolysaccharide (LPS) is an important structural component, and is also involved in colonization and resistance to host immune response.

• #13 Disease information about Invasive Haemophilus influenzae disease

  https://www.ecdc.europa.eu/en/invasive-haemophilus-influenzae-disease/facts

  Haemophilus influenzae serotype b (Hib) is the most common cause of bacterial meningitis in children aged two months to five years, in those countries where suitable vaccination programmes are not in place. […] Haemophilus influenzae type b is an encapsulated, immotile and non-spore forming Gram-negative coccobacillus. […] Serotype b (Hib) has a polyribosyl ribitol phosphate (PRP) polysaccharide capsule that is a major virulence factor. […] The PRP capsule protects the organism from phagocytosis in the absence of anticapsular antibodies and facilitates penetration to the blood stream and the cerebrospinal fluid. […] Haemophilus influenzae type b causes pneumonia, septicaemia, meningitis, epiglottitis, septic arthritis, cellulitis, otitis media, and purulent pericarditis, as well as less common invasive infections such as endocarditis, osteomyelitis, and peritonitis.

• #14 Haemophilus Influenzae Infections: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/964317-overview

  Haemophilus influenzae is a small (1 m X 0.3 m), pleomorphic, gram-negative coccobacillus. Some strains of H influenzae possess a polysaccharide capsule. The most virulent strain is H influenzae type b (Hib), with its polyribosyl ribitol phosphate (PRP) capsule. It accounts for more than 95% of H influenzae invasive diseases in children and half of invasive diseases in adults, including bacteremia, meningitis, cellulitis, epiglottitis, septic arthritis, pneumonia, and empyema. […] The antiphagocytic nature of the Hib capsule and the absence of the anticapsular antibody lead to increasing bacterial proliferation. When the bacterial concentration exceeds a critical level, it can disseminate to various sites, including meninges, subcutaneous tissue, joints, pleura, pericardia, and lungs. […] The Hib conjugate vaccine induces protection by inducing antibodies against the PRP capsule. The Hib conjugate vaccine does not provide protection against NTHi strains. Since the widespread use of the Hib conjugate vaccine, NTHi has become a more common pathogen.

• #15 Haemophilus influenzae infection – wikidoc

  https://www.wikidoc.org/index.php/Haemophilus_influenzae_infection

  H. influenzae is a gram-negative, cocco-bacillary, facultatively anaerobic pathogenic bacterium that can cause infections in people of all ages ranging from mild, such as an ear infection, to severe, such as a bloodstream infection. […] The pathogenesis of H.influenzae infections can be described as follows: […] The capsule of H influenza plays a key role in the pathogenesis of the all the capsulated H influenza infections. […] The antiphagocytic nature of the Hib capsule makes it resistant to natural host phagocytic defense mechanisms and facilitating bacterial proliferation. […] After proliferation, the bacterial load disseminates to various sites, including meninges, subcutaneous tissue, joints, pleura, pericardium, and lungs triggering an inflammatory response and subsequently activating the complement system.

• #16 Chapter 8: Haemophilus influenzae | Pink Book | CDC

  https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-8-haemophilus-influenzae.html

  Haemophilus influenzae enters the body through the nasopharynx. […] In some persons, H. influenzae causes an invasive infection. […] The bacteria spread in the bloodstream to distant sites in the body. […] Incidence is strikingly age-dependent. […] Antibodies to Hib capsular polysaccharide are protective. […] The genetic constitution of the host may also be important in susceptibility to Hib infection.

• #17 Haemophilus Species – Medical Microbiology – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK8458/

  Type b Haemophilus influenzae colonizes the nasopharynx, and may penetrate the epithelium and capillary endothelium to cause bacteremia. Meningitis may result from direct spread via lymphatic drainage or from hematogenous spread. Nontypable H influenzae colonizes the nasopharynx and, to a lesser extent, the trachea and bronchi and may infect mucosa damaged by viral disease or cigarette smoking. Lipooligosaccharide is largely responsible for inflammation; exotoxins do not play a role. […] The pathogenesis of H influenzae infections is not completely understood, but the presence of the type b polysaccharide capsule is a major factor in virulence. Encapsulated organisms can penetrate the epithelium of the nasopharynx and invade blood capillaries directly. Nontypable strains are less invasive, but they, as well as typable strains, induce an inflammatory response that causes disease; production of exotoxins is not thought to play a role in pathogenicity. Nontypable H influenzae strains colonize the nasopharynx of most normal individuals, but type b H influenzae strains are found in only 1 to 2 percent of normal children. Outbreaks of type b infection occur, especially in nurseries and child care centers; prophylactic administration of antibiotics may be used. Vaccination with type b polysaccharide appears to be effective in preventing infection, and vaccines are now available for routine use.

• #18 Haemophilus Species – Medical Microbiology – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK8458/

  The pathogenesis of meningitis due to type b H influenzae has been well studied. These organisms colonize the nasopharynx and spread from one human to another by direct contact or via secretions and/or aerosol. They penetrate epithelial layers and capillary endothelium by unknown mechanisms, reaching the meninges either directly via lymphatic drainage from the nasopharynx or indirectly by causing bacteremia with subsequent seeding of the highly vascular choroid plexus.

• #19 Haemophilus influenzae: Infectious substances pathogen safety data sheet – Canada.ca

  https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/haemophilus-influenzae-type-b.html

  Haemophilus influenzae is differentiated into six capsular types (a to f) according to its capsular polysaccharide structure. […] The most virulent serotype is H. influenzae type b (Hib), and its capsule, composed of polyribosyl ribitol phosphate (PRP), is the predominant virulence determinant. […] The capsule confers antiphagocytic properties to the bacteria and increases proliferation. […] Proteins such as Haemophilus surface fibrils (Hsf) and protein H are present on encapsulated strains and aid in adherence to the host cells. […] Outer-membrane proteins contribute to virulence and some are thought to be involved in invasion of mucosal epithelium. […] Pili mediate bacterial adherence to mucosal surfaces and facilitate respiratory tract colonization. […] H. influenzae secretes immunoglobulin A1 (IgA1) which acts to inactivate human IgA1, thus evading host immune function and promoting colonization. […] The lipopolysaccharide (LPS) is an important structural component, and is also involved in colonization and resistance to host immune response.

• #20 Haemophilus influenzae: Infectious substances pathogen safety data sheet – Canada.ca

  https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/haemophilus-influenzae-type-b.html

  Haemophilus influenzae is differentiated into six capsular types (a to f) according to its capsular polysaccharide structure. […] The most virulent serotype is H. influenzae type b (Hib), and its capsule, composed of polyribosyl ribitol phosphate (PRP), is the predominant virulence determinant. […] The capsule confers antiphagocytic properties to the bacteria and increases proliferation. […] Proteins such as Haemophilus surface fibrils (Hsf) and protein H are present on encapsulated strains and aid in adherence to the host cells. […] Outer-membrane proteins contribute to virulence and some are thought to be involved in invasion of mucosal epithelium. […] Pili mediate bacterial adherence to mucosal surfaces and facilitate respiratory tract colonization. […] H. influenzae secretes immunoglobulin A1 (IgA1) which acts to inactivate human IgA1, thus evading host immune function and promoting colonization. […] The lipopolysaccharide (LPS) is an important structural component, and is also involved in colonization and resistance to host immune response.

• #21 Haemophilus Species – Medical Microbiology – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK8458/

  Type b Haemophilus influenzae colonizes the nasopharynx, and may penetrate the epithelium and capillary endothelium to cause bacteremia. Meningitis may result from direct spread via lymphatic drainage or from hematogenous spread. Nontypable H influenzae colonizes the nasopharynx and, to a lesser extent, the trachea and bronchi and may infect mucosa damaged by viral disease or cigarette smoking. Lipooligosaccharide is largely responsible for inflammation; exotoxins do not play a role. […] The pathogenesis of H influenzae infections is not completely understood, but the presence of the type b polysaccharide capsule is a major factor in virulence. Encapsulated organisms can penetrate the epithelium of the nasopharynx and invade blood capillaries directly. Nontypable strains are less invasive, but they, as well as typable strains, induce an inflammatory response that causes disease; production of exotoxins is not thought to play a role in pathogenicity. Nontypable H influenzae strains colonize the nasopharynx of most normal individuals, but type b H influenzae strains are found in only 1 to 2 percent of normal children. Outbreaks of type b infection occur, especially in nurseries and child care centers; prophylactic administration of antibiotics may be used. Vaccination with type b polysaccharide appears to be effective in preventing infection, and vaccines are now available for routine use.

• #22 Haemophilus Species – Medical Microbiology – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK8458/

  The pathogenesis of meningitis due to type b H influenzae has been well studied. These organisms colonize the nasopharynx and spread from one human to another by direct contact or via secretions and/or aerosol. They penetrate epithelial layers and capillary endothelium by unknown mechanisms, reaching the meninges either directly via lymphatic drainage from the nasopharynx or indirectly by causing bacteremia with subsequent seeding of the highly vascular choroid plexus.

• #23 Haemophilus Species – Medical Microbiology – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK8458/

  The pathogenesis of meningitis due to type b H influenzae has been well studied. These organisms colonize the nasopharynx and spread from one human to another by direct contact or via secretions and/or aerosol. They penetrate epithelial layers and capillary endothelium by unknown mechanisms, reaching the meninges either directly via lymphatic drainage from the nasopharynx or indirectly by causing bacteremia with subsequent seeding of the highly vascular choroid plexus.

• #24 Haemophilus influenzae: Infectious substances pathogen safety data sheet – Canada.ca

  https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/haemophilus-influenzae-type-b.html

  Haemophilus influenzae is differentiated into six capsular types (a to f) according to its capsular polysaccharide structure. […] The most virulent serotype is H. influenzae type b (Hib), and its capsule, composed of polyribosyl ribitol phosphate (PRP), is the predominant virulence determinant. […] The capsule confers antiphagocytic properties to the bacteria and increases proliferation. […] Proteins such as Haemophilus surface fibrils (Hsf) and protein H are present on encapsulated strains and aid in adherence to the host cells. […] Outer-membrane proteins contribute to virulence and some are thought to be involved in invasion of mucosal epithelium. […] Pili mediate bacterial adherence to mucosal surfaces and facilitate respiratory tract colonization. […] H. influenzae secretes immunoglobulin A1 (IgA1) which acts to inactivate human IgA1, thus evading host immune function and promoting colonization. […] The lipopolysaccharide (LPS) is an important structural component, and is also involved in colonization and resistance to host immune response.

• #25 Haemophilus influenzae: Infectious substances pathogen safety data sheet – Canada.ca

  https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/haemophilus-influenzae-type-b.html

  Haemophilus influenzae is differentiated into six capsular types (a to f) according to its capsular polysaccharide structure. […] The most virulent serotype is H. influenzae type b (Hib), and its capsule, composed of polyribosyl ribitol phosphate (PRP), is the predominant virulence determinant. […] The capsule confers antiphagocytic properties to the bacteria and increases proliferation. […] Proteins such as Haemophilus surface fibrils (Hsf) and protein H are present on encapsulated strains and aid in adherence to the host cells. […] Outer-membrane proteins contribute to virulence and some are thought to be involved in invasion of mucosal epithelium. […] Pili mediate bacterial adherence to mucosal surfaces and facilitate respiratory tract colonization. […] H. influenzae secretes immunoglobulin A1 (IgA1) which acts to inactivate human IgA1, thus evading host immune function and promoting colonization. […] The lipopolysaccharide (LPS) is an important structural component, and is also involved in colonization and resistance to host immune response.

• #26 Haemophilus Species – Medical Microbiology – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK8458/

  Type b Haemophilus influenzae colonizes the nasopharynx, and may penetrate the epithelium and capillary endothelium to cause bacteremia. Meningitis may result from direct spread via lymphatic drainage or from hematogenous spread. Nontypable H influenzae colonizes the nasopharynx and, to a lesser extent, the trachea and bronchi and may infect mucosa damaged by viral disease or cigarette smoking. Lipooligosaccharide is largely responsible for inflammation; exotoxins do not play a role. […] The pathogenesis of H influenzae infections is not completely understood, but the presence of the type b polysaccharide capsule is a major factor in virulence. Encapsulated organisms can penetrate the epithelium of the nasopharynx and invade blood capillaries directly. Nontypable strains are less invasive, but they, as well as typable strains, induce an inflammatory response that causes disease; production of exotoxins is not thought to play a role in pathogenicity. Nontypable H influenzae strains colonize the nasopharynx of most normal individuals, but type b H influenzae strains are found in only 1 to 2 percent of normal children. Outbreaks of type b infection occur, especially in nurseries and child care centers; prophylactic administration of antibiotics may be used. Vaccination with type b polysaccharide appears to be effective in preventing infection, and vaccines are now available for routine use.

• #27 Haemophilus Influenzae Infections: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/964317-overview

  Although NTHi lacks a polysaccharide capsule, the expression of lipooligosaccharides (LOS) allow it to adhere and evade complement-mediated responses contributing to its virulence. […] NTHi strains form biofilm in vitro and ex vivo and have been implicated in chronic infection such as otitis media, sinusitis, and bronchitis.

• #28 Haemophilus influenzae: Infectious substances pathogen safety data sheet – Canada.ca

  https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/haemophilus-influenzae-type-b.html

  Haemophilus influenzae is differentiated into six capsular types (a to f) according to its capsular polysaccharide structure. […] The most virulent serotype is H. influenzae type b (Hib), and its capsule, composed of polyribosyl ribitol phosphate (PRP), is the predominant virulence determinant. […] The capsule confers antiphagocytic properties to the bacteria and increases proliferation. […] Proteins such as Haemophilus surface fibrils (Hsf) and protein H are present on encapsulated strains and aid in adherence to the host cells. […] Outer-membrane proteins contribute to virulence and some are thought to be involved in invasion of mucosal epithelium. […] Pili mediate bacterial adherence to mucosal surfaces and facilitate respiratory tract colonization. […] H. influenzae secretes immunoglobulin A1 (IgA1) which acts to inactivate human IgA1, thus evading host immune function and promoting colonization. […] The lipopolysaccharide (LPS) is an important structural component, and is also involved in colonization and resistance to host immune response.

• #29 Haemophilus influenzae: Infectious substances pathogen safety data sheet – Canada.ca

  https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/haemophilus-influenzae-type-b.html

  Haemophilus influenzae is differentiated into six capsular types (a to f) according to its capsular polysaccharide structure. […] The most virulent serotype is H. influenzae type b (Hib), and its capsule, composed of polyribosyl ribitol phosphate (PRP), is the predominant virulence determinant. […] The capsule confers antiphagocytic properties to the bacteria and increases proliferation. […] Proteins such as Haemophilus surface fibrils (Hsf) and protein H are present on encapsulated strains and aid in adherence to the host cells. […] Outer-membrane proteins contribute to virulence and some are thought to be involved in invasion of mucosal epithelium. […] Pili mediate bacterial adherence to mucosal surfaces and facilitate respiratory tract colonization. […] H. influenzae secretes immunoglobulin A1 (IgA1) which acts to inactivate human IgA1, thus evading host immune function and promoting colonization. […] The lipopolysaccharide (LPS) is an important structural component, and is also involved in colonization and resistance to host immune response.

• #30 Haemophilus Meningitis: Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/1164916-overview

  Haemophilus strains may be encapsulated or unencapsulated. Encapsulated strains (also known as typeable) are surrounded by a polysaccharide capsule that plays an important role in the determination of virulence of the organism. The outer membrane lipo-oligosaccharides also contribute to the degree of virulence. Encapsulated strains are divided, on the basis of capsular antigens, into 6 serotypes designated a through f. Unencapsulated strains lack the polysaccharide capsule and are designated untypable strains. […] The capacity to eliminate Haemophilus from the circulation clearly entails normal function of the spleen as well as humoral and cellular arms of the immune system, because infections are more common in individuals who have defects in these systems. […] Passage into both the blood circulation and the immunologically privileged CNS appears to involve not only capsular epitopes that do not arouse an effective host immune response but also epitopes that may facilitate bacterial attachment to given endothelial receptors and subsequent invasiveness in target sites. Invasiveness likely also involves the capacity to develop and then shed such attachment-related devices as bacterial fimbriae.

• #31 Chapter 8: Haemophilus influenzae | Pink Book | CDC

  https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-8-haemophilus-influenzae.html

  Haemophilus influenzae enters the body through the nasopharynx. […] In some persons, H. influenzae causes an invasive infection. […] The bacteria spread in the bloodstream to distant sites in the body. […] Incidence is strikingly age-dependent. […] Antibodies to Hib capsular polysaccharide are protective. […] The genetic constitution of the host may also be important in susceptibility to Hib infection.

• #32 Haemophilus influenzae – Wikipedia

  https://en.wikipedia.org/wiki/Haemophilus_influenzae

  Naturally acquired disease caused by H. influenzaeseems to occur in humans only. […] In healthy children under the age of 5,H. influenzaetype b was responsible for more than 80% of aggressive infections, before the introduction of the [Hib] vaccine. […] In infants and young children,H. influenzaetype b (Hib) causes bacteremia, pneumonia, epiglottitis and acute bacterial meningitis. […] However, Hib remains a major cause of lower respiratory tract infections in infants and children in developing countries where the vaccine is not widely used.

• #33 Chapter 8: Haemophilus influenzae | Pink Book | CDC

  https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-8-haemophilus-influenzae.html

  Haemophilus influenzae enters the body through the nasopharynx. […] In some persons, H. influenzae causes an invasive infection. […] The bacteria spread in the bloodstream to distant sites in the body. […] Incidence is strikingly age-dependent. […] Antibodies to Hib capsular polysaccharide are protective. […] The genetic constitution of the host may also be important in susceptibility to Hib infection.

• #34 Haemophilus influenzae – Wikipedia

  https://en.wikipedia.org/wiki/Haemophilus_influenzae

  Naturally acquired disease caused by H. influenzaeseems to occur in humans only. […] In healthy children under the age of 5,H. influenzaetype b was responsible for more than 80% of aggressive infections, before the introduction of the [Hib] vaccine. […] In infants and young children,H. influenzaetype b (Hib) causes bacteremia, pneumonia, epiglottitis and acute bacterial meningitis. […] However, Hib remains a major cause of lower respiratory tract infections in infants and children in developing countries where the vaccine is not widely used.

• #35 Haemophilus influenzae type b (Hib) | Better Health Channel

  https://www.betterhealth.vic.gov.au/health/healthyliving/haemophilus-influenzae-type-b-hib

  Haemophilus influenzae type b (Hib) is a bacterium that causes a life-threatening infection that can lead to serious illness, especially in children. […] Disease caused by Hib is spread mainly through person-to-person contact with infected droplets (coughing or sneezing) or secretions from an infected person’s nose and throat. […] There are several types of Haemophilus influenzae bacteria and infection with the type b (Hib) bacterium can cause a range of conditions in vulnerable people, some of which are medical emergencies. […] The usual time between contact with the bacteria and the development of the illness is around two to four days. The person with Hib is infectious for as long as the bacteria stays in the nose or throat. Generally 24 to 48 hours of appropriate antibiotic treatment is required to clear the infection.

• #36 Haemophilus Influenzae: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/23106-haemophilus-influenzae

  Haemophilus influenzae type b spreads from person to person through respiratory droplets in coughs and sneezes. The respiratory droplets contain the bacteria, and other people can get sick when they breathe in the droplets. […] Haemophilus influenzae treatment depends on the type of infection or disease. Treatment usually includes the use of antibiotics to fight the infection. However, H. influenzae can be resistant to antibiotics. Depending on the severity of your condition, you may need additional treatment in the hospital.

• #37 Haemophilus Influenzae: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/23106-haemophilus-influenzae

  Haemophilus influenzae is a type of bacteria that can cause several different kinds of infections. These bacterial infections can range from mild, such as ear infections, to severe, such as bloodstream infections. […] Some H. influenzae infections are invasive, which means the bacteria invade parts of your body that are normally free from germs. For instance, H. influenzae can invade the fluid surrounding your spinal cord and brain, which can cause meningitis. Meningitis is the swelling of the lining of your brain and spinal cord. Invasive diseases usually require hospital treatment and can sometimes be fatal. […] Type b, or Hib, causes 95% of all severe invasive infections. […] These bacteria live in your nose and throat but they usually don’t cause any harm. When the bacteria move to other parts of your body, they can cause infections.

• #38 Haemophilus Species – Medical Microbiology – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK8458/

  Type b Haemophilus influenzae colonizes the nasopharynx, and may penetrate the epithelium and capillary endothelium to cause bacteremia. Meningitis may result from direct spread via lymphatic drainage or from hematogenous spread. Nontypable H influenzae colonizes the nasopharynx and, to a lesser extent, the trachea and bronchi and may infect mucosa damaged by viral disease or cigarette smoking. Lipooligosaccharide is largely responsible for inflammation; exotoxins do not play a role. […] The pathogenesis of H influenzae infections is not completely understood, but the presence of the type b polysaccharide capsule is a major factor in virulence. Encapsulated organisms can penetrate the epithelium of the nasopharynx and invade blood capillaries directly. Nontypable strains are less invasive, but they, as well as typable strains, induce an inflammatory response that causes disease; production of exotoxins is not thought to play a role in pathogenicity. Nontypable H influenzae strains colonize the nasopharynx of most normal individuals, but type b H influenzae strains are found in only 1 to 2 percent of normal children. Outbreaks of type b infection occur, especially in nurseries and child care centers; prophylactic administration of antibiotics may be used. Vaccination with type b polysaccharide appears to be effective in preventing infection, and vaccines are now available for routine use.

• #39

  https://www.gov.uk/government/publications/haemophilus-influenzae-type-b-hib-revised-recommendations-for-the-prevention-of-secondary-cases/revised-recommendations-for-the-prevention-of-secondary-haemophilus-influenzae-type-b-hib-disease

  Haemophilus influenzae type b (Hib) can cause severe life-threatening disease in healthy individuals and is a major global cause of childhood meningitis, pneumonia, epiglottitis, septicaemia, cellulitis, osteomyelitis and septic arthritis. […] The organism can be carried asymptomatically in the naso- and oro-pharynx and acquisition most commonly results from asymptomatic carriers, rather than from cases. […] Individuals may transfer the organism to close contacts though airborne or droplet spread by coughing and sneezing. […] The introduction of Hib conjugate vaccine into routine childhood immunisation programmes has initially resulted in a greater than 90% reduction in the incidence of invasive Hib disease, through a combination of direct and indirect (herd immunity) protection. […] Compared to the general population, close contacts of individuals with invasive Hib disease (particularly in a household or pre-school setting) are at increased risk of developing invasive Hib disease compared with the general population.

• #40 Haemophilus influenzae type b (Hib) | Better Health Channel

  https://www.betterhealth.vic.gov.au/health/healthyliving/haemophilus-influenzae-type-b-hib

  Haemophilus influenzae type b (Hib) is a bacterium that causes a life-threatening infection that can lead to serious illness, especially in children. […] Disease caused by Hib is spread mainly through person-to-person contact with infected droplets (coughing or sneezing) or secretions from an infected person’s nose and throat. […] There are several types of Haemophilus influenzae bacteria and infection with the type b (Hib) bacterium can cause a range of conditions in vulnerable people, some of which are medical emergencies. […] The usual time between contact with the bacteria and the development of the illness is around two to four days. The person with Hib is infectious for as long as the bacteria stays in the nose or throat. Generally 24 to 48 hours of appropriate antibiotic treatment is required to clear the infection.

• #41 Haemophilus Species – Medical Microbiology – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK8458/

  Type b Haemophilus influenzae colonizes the nasopharynx, and may penetrate the epithelium and capillary endothelium to cause bacteremia. Meningitis may result from direct spread via lymphatic drainage or from hematogenous spread. Nontypable H influenzae colonizes the nasopharynx and, to a lesser extent, the trachea and bronchi and may infect mucosa damaged by viral disease or cigarette smoking. Lipooligosaccharide is largely responsible for inflammation; exotoxins do not play a role. […] The pathogenesis of H influenzae infections is not completely understood, but the presence of the type b polysaccharide capsule is a major factor in virulence. Encapsulated organisms can penetrate the epithelium of the nasopharynx and invade blood capillaries directly. Nontypable strains are less invasive, but they, as well as typable strains, induce an inflammatory response that causes disease; production of exotoxins is not thought to play a role in pathogenicity. Nontypable H influenzae strains colonize the nasopharynx of most normal individuals, but type b H influenzae strains are found in only 1 to 2 percent of normal children. Outbreaks of type b infection occur, especially in nurseries and child care centers; prophylactic administration of antibiotics may be used. Vaccination with type b polysaccharide appears to be effective in preventing infection, and vaccines are now available for routine use.

• #42 Haemophilus Meningitis: Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/1164916-overview

  The polysaccharide capsule of these organisms not only confers virulence and invasiveness but also provides resistance to opsonization and complement-mediated bactericidal activities and inhibits neutrophil phagocytosis. […] The development of resistance to Hib infection appears to be due to gradual acquisition of antibodies directed at capsular determinants of Hib and possibly to other aspects of immune system maturation.

• #43 Chapter 8: Haemophilus influenzae | Pink Book | CDC

  https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-8-haemophilus-influenzae.html

  Haemophilus influenzae enters the body through the nasopharynx. […] In some persons, H. influenzae causes an invasive infection. […] The bacteria spread in the bloodstream to distant sites in the body. […] Incidence is strikingly age-dependent. […] Antibodies to Hib capsular polysaccharide are protective. […] The genetic constitution of the host may also be important in susceptibility to Hib infection.

• #44 Haemophilus influenzae Type b Vaccine – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK553112/

  The composition of the polysaccharide capsule of Hib is polyribosyl ribitol phosphate (PRP), which, like other polysaccharide capsules, acts as an antigen that does not recruit T-cells. Therefore, the polysaccharide form of the vaccine is not immunogenic before the age of 2 because only small numbers of antibodies form via the T-cell-independent immune process. The conjugate form of the vaccine is made by covalently attaching the PRP capsule to a protein, which recruits T-cells and leads to the formation of sufficient numbers of anti-PRP antibodies. […] Research has shown that the use of the Hib vaccine in combination with the acellular pertussis vaccine, as is the case in diphtheria and tetanus toxoids and acellular pertussis adsorbed inactivated poliovirus, and Haemophilus b conjugate (tetanus toxoid conjugate) vaccine (DTaP-IPV/Hib) has been shown to decrease the immunogenicity and possibly contribute to the Hib vaccine failures. Importantly, administration of the Hib vaccine and DTap (which contains acellular pertussis) at the same appointment but in different injection sites has shown no evidence of decreased Hib immunogenicity or increased Hib vaccine failures.

• #45

  https://link.springer.com/article/10.1007/BF03259300

  Haemophilus influenzae type b (Hib) conjugate vaccines represent a new technology wherein an immunogen is targeted to a specific immune response mechanism. Covalent attachment of the Hib polysaccharide to a protein carrier converts the T cell-independent polysaccharide antigen into a protein-like T cell-dependent antigen. The polysaccharide alone is poorly immunogenic in infants (12 months old), and conjugation to a protein carrier results in a protein-like antibody response to the Hib polysaccharide in infants. Conjugate vaccines induce mostly IgG antibodies and immunological memory. Later vaccination or natural exposure then induces a booster response to the Hib polysaccharide. […] These conjugate vaccines have dramatically reduced the incidence of Hib disease in many industrialised countries, and also reduce nasopharyngeal carriage of Hib in unvaccinated children in populations in which the vaccine is used. The Hib conjugates have now been combined with diphtheria and tetanus toxoids and pertussis vaccine to reduce the number of injections required for infants. Finally, the conjugate technology that has permitted the near elimination of Hib disease has now been extended to other invasive encapsulated bacterial pathogens.

• #46 Haemophilus influenzae Type b Vaccine – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK553112/

  The composition of the polysaccharide capsule of Hib is polyribosyl ribitol phosphate (PRP), which, like other polysaccharide capsules, acts as an antigen that does not recruit T-cells. Therefore, the polysaccharide form of the vaccine is not immunogenic before the age of 2 because only small numbers of antibodies form via the T-cell-independent immune process. The conjugate form of the vaccine is made by covalently attaching the PRP capsule to a protein, which recruits T-cells and leads to the formation of sufficient numbers of anti-PRP antibodies. […] Research has shown that the use of the Hib vaccine in combination with the acellular pertussis vaccine, as is the case in diphtheria and tetanus toxoids and acellular pertussis adsorbed inactivated poliovirus, and Haemophilus b conjugate (tetanus toxoid conjugate) vaccine (DTaP-IPV/Hib) has been shown to decrease the immunogenicity and possibly contribute to the Hib vaccine failures. Importantly, administration of the Hib vaccine and DTap (which contains acellular pertussis) at the same appointment but in different injection sites has shown no evidence of decreased Hib immunogenicity or increased Hib vaccine failures.

• #47

  https://link.springer.com/article/10.1007/BF03259300

  Haemophilus influenzae type b (Hib) conjugate vaccines represent a new technology wherein an immunogen is targeted to a specific immune response mechanism. Covalent attachment of the Hib polysaccharide to a protein carrier converts the T cell-independent polysaccharide antigen into a protein-like T cell-dependent antigen. The polysaccharide alone is poorly immunogenic in infants (12 months old), and conjugation to a protein carrier results in a protein-like antibody response to the Hib polysaccharide in infants. Conjugate vaccines induce mostly IgG antibodies and immunological memory. Later vaccination or natural exposure then induces a booster response to the Hib polysaccharide. […] These conjugate vaccines have dramatically reduced the incidence of Hib disease in many industrialised countries, and also reduce nasopharyngeal carriage of Hib in unvaccinated children in populations in which the vaccine is used. The Hib conjugates have now been combined with diphtheria and tetanus toxoids and pertussis vaccine to reduce the number of injections required for infants. Finally, the conjugate technology that has permitted the near elimination of Hib disease has now been extended to other invasive encapsulated bacterial pathogens.

• #48 Hib vaccine | EBSCO Research Starters

  https://www.ebsco.com/research-starters/health-and-medicine/hib-vaccine

  The Hib vaccine is made by taking the shell (the polysaccharide coating) of the Hib bacterium and linking it to another protein. Injection of this safe combination incites the body to produce an immune response against this Hib bacteria coating without actually causing the disease, thus protecting against future infection. […] The Hib vaccine is highly effective at preventing the diseases commonly caused by the bacterium H. influenzae. Before the development of this vaccine, Hib was the leading cause of meningitis in children. It is estimated that the mortality rate among infants and children who contracted this illness was 5 percent, with an even greater incidence of permanent brain damage or hearing loss, or both, among survivors. […] Epiglottitis, a serious disease most commonly caused by Hib, was widespread before Hib vaccination became standard. However, it has virtually disappeared as a disease, and many pediatricians have learned of this illness only by anecdote.

• #49 Systematic Evaluation of the Distribution of Immune Cells following Subcutaneous Administration of Haemophilus Influenzae Type B Vaccine to Mice

  https://www.mdpi.com/2079-9721/11/4/139

  The Haemophilus influenzae type B (Hib) conjugate vaccine is the most effective way to prevent Hib infection in infants and young children, and it is designed to induce the production of antibodies against polyribosylribitol phosphate (PRP) to protect babies from infection. However, the mechanism of immunity induced by the Hib vaccine is not fully understood. […] Understanding the mechanism of the Hib-vaccine-induced immune response and the influence of adjuvants on the Hib vaccine is of great significance. […] We found that the Hib vaccine could induce a humoral and cellular immune response, and the Hib-Al vaccine could induce greater quantities of IFN-γ, IL-4, and IL-6 and more antigen-specific antibodies through B cells, Th1, Th2, and ILC3s in the spleen. Together, our findings demonstrate the serologic responses and immune response in terms of cell and cytokine levels induced by the Hib vaccine, and they also imply that the addition of aluminum hydroxide adjuvant could enhance the function of the Hib vaccine, which preliminarily reveals the mechanism of immune response induced by the Hib-related vaccine.

• #50 Systematic Evaluation of the Distribution of Immune Cells following Subcutaneous Administration of Haemophilus Influenzae Type B Vaccine to Mice

  https://www.mdpi.com/2079-9721/11/4/139

  The immunogenicity of Hib vaccines is thought to test the anti-PRR antibody level. […] The mechanisms underlying the immunogenicity of conjugate vaccines remain poorly understood. […] The humoral and cellular immune response to the Hib and Hib+Al vaccines could address the question of whether the addition of an aluminum adjuvant to the Hib vaccine could have a protective function. […] The results show that both the Hib and Hib+Al vaccines induce a humoral immune response, including anti-PRP antibody and GCBs. However, the Hib+Al vaccine induced a higher level of anti-PRP antibody and more GCB cells than the Hib vaccine, suggesting that the aluminum hydroxide adjuvant could enhance the humoral immune response in the Hib vaccine. […] The aluminum adjuvant may induce a Th1 response. […] The results show that the Hib and Hib+Al vaccines induced IL-2, IL-6, and IFN-γ expression, suggesting that the Hib vaccine could induce cellular immune response and antibody production.

• #51 Systematic Evaluation of the Distribution of Immune Cells following Subcutaneous Administration of Haemophilus Influenzae Type B Vaccine to Mice

  https://www.mdpi.com/2079-9721/11/4/139

  The addition of the aluminum adjuvant could induce a stronger immune response, including the cellular and humoral immune response. […] The addition of the aluminum adjuvant upregulated both the Th1 and Th2 cell response and decreased the ILC3 expression. These results reveal that the addition of the adjuvant in the Hib vaccine was beneficial for inducing a stronger immune response, which provides theoretical support for the development of subsequent combination vaccines.

• #52 Disease information about Invasive Haemophilus influenzae disease

  https://www.ecdc.europa.eu/en/invasive-haemophilus-influenzae-disease/facts

  Haemophilus influenzae type b is responsible for 95% of all invasive H. influenzae infections in unimmunised populations and it is an important cause of severe and sometimes fatal infections, particularly in young children. […] The Hib conjugate vaccine is highly effective in eradicating asymptomatic Hib carriage and, in countries that routinely immunise against Hib in infancy, vaccinated children are rarely colonised. […] The Hib conjugate vaccine, which consists of the polyribosylribitol phosphate (PRP) polysaccharide from the Hib capsule conjugated to a protein carrier, prevents invasive Hib disease and reduces naso-pharyngeal carriage.

• #53

  https://link.springer.com/article/10.1007/BF03259300

  Haemophilus influenzae type b (Hib) conjugate vaccines represent a new technology wherein an immunogen is targeted to a specific immune response mechanism. Covalent attachment of the Hib polysaccharide to a protein carrier converts the T cell-independent polysaccharide antigen into a protein-like T cell-dependent antigen. The polysaccharide alone is poorly immunogenic in infants (12 months old), and conjugation to a protein carrier results in a protein-like antibody response to the Hib polysaccharide in infants. Conjugate vaccines induce mostly IgG antibodies and immunological memory. Later vaccination or natural exposure then induces a booster response to the Hib polysaccharide. […] These conjugate vaccines have dramatically reduced the incidence of Hib disease in many industrialised countries, and also reduce nasopharyngeal carriage of Hib in unvaccinated children in populations in which the vaccine is used. The Hib conjugates have now been combined with diphtheria and tetanus toxoids and pertussis vaccine to reduce the number of injections required for infants. Finally, the conjugate technology that has permitted the near elimination of Hib disease has now been extended to other invasive encapsulated bacterial pathogens.

• #54

  https://link.springer.com/article/10.1007/BF03259300

  Haemophilus influenzae type b (Hib) conjugate vaccines represent a new technology wherein an immunogen is targeted to a specific immune response mechanism. Covalent attachment of the Hib polysaccharide to a protein carrier converts the T cell-independent polysaccharide antigen into a protein-like T cell-dependent antigen. The polysaccharide alone is poorly immunogenic in infants (12 months old), and conjugation to a protein carrier results in a protein-like antibody response to the Hib polysaccharide in infants. Conjugate vaccines induce mostly IgG antibodies and immunological memory. Later vaccination or natural exposure then induces a booster response to the Hib polysaccharide. […] These conjugate vaccines have dramatically reduced the incidence of Hib disease in many industrialised countries, and also reduce nasopharyngeal carriage of Hib in unvaccinated children in populations in which the vaccine is used. The Hib conjugates have now been combined with diphtheria and tetanus toxoids and pertussis vaccine to reduce the number of injections required for infants. Finally, the conjugate technology that has permitted the near elimination of Hib disease has now been extended to other invasive encapsulated bacterial pathogens.

• #55 Haemophilus Influenzae Infections: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/964317-overview

  Haemophilus influenzae is a small (1 m X 0.3 m), pleomorphic, gram-negative coccobacillus. Some strains of H influenzae possess a polysaccharide capsule. The most virulent strain is H influenzae type b (Hib), with its polyribosyl ribitol phosphate (PRP) capsule. It accounts for more than 95% of H influenzae invasive diseases in children and half of invasive diseases in adults, including bacteremia, meningitis, cellulitis, epiglottitis, septic arthritis, pneumonia, and empyema. […] The antiphagocytic nature of the Hib capsule and the absence of the anticapsular antibody lead to increasing bacterial proliferation. When the bacterial concentration exceeds a critical level, it can disseminate to various sites, including meninges, subcutaneous tissue, joints, pleura, pericardia, and lungs. […] The Hib conjugate vaccine induces protection by inducing antibodies against the PRP capsule. The Hib conjugate vaccine does not provide protection against NTHi strains. Since the widespread use of the Hib conjugate vaccine, NTHi has become a more common pathogen.

• #56 Haemophilus influenzae infection – wikidoc

  https://www.wikidoc.org/index.php/Haemophilus_influenzae_infection

  Capsulated H influenza can penetrate the normal epithelium and are therefore responsible for invasive infections. […] Non-capsulated are non-invasive but can still induce the inflammatory response similar to that of capsulated organisms. […] The Hib conjugate vaccine induces protection by inducing antibodies against the PRP capsule. […] The Hib conjugate vaccine does not provide protection against Non-typable H influenza strains. Since the widespread use of the Hib conjugate vaccine, Non-typable H influenza strains has become more of a pathogen.

• #57 Haemophilus Influenzae Type B (Hib): The Disease & Vaccines | Children’s Hospital of Philadelphia

  https://www.chop.edu/vaccine-education-center/vaccine-details/haemophilus-influenzae-type-b-hib-vaccine

  Haemophilus influenzae type b (Hib) is a bacterium that infects the lining of the brain, causing meningitis. Meningitis is caused by several different bacteria. However, before the Hib vaccine, Hib was by far the most common cause of meningitis. […] The Hib vaccine is made from the sugar coating (polysaccharide) of the bacteria. Antibodies directed against the Hib polysaccharide protect the child against an infection that could result in permanent disabilities or death. […] Scientists have figured out that by taking the Hib polysaccharide and linking it to a harmless protein, young children are able to make a stronger immune response to the polysaccharide. This conjugated version of the Hib vaccine works extremely well. […] The Hib vaccine has caused a dramatic decline in the incidence of meningitis, bloodstream infections, and pneumonia caused by Hib. However, Hib bacteria still circulate in the community and occasionally cause disease.

• #58

  https://historyofvaccines.org/diseases/hib-haemophilus-influenzae-type-b/

  Haemophilus Influenzae type b, commonly known as Hib, is a bacterium that can cause severe infections, particularly in young children. Hib bacteria can cause many types of invasive disease, including meningitis, pneumonia, cellulitis (skin infection), septic arthritis (joint infection) and epiglottitis (infection of the epiglottis, causing obstruction or closing of the windpipe). […] Before the Hib vaccine was introduced, meningitis infection of the membranes that cover the brain was the most common Hib-induced invasive disease. […] Because the spectrum of Hib disease ranges from meningitis to pneumonia, the types of complications vary depending on the type of Hib infection. Many of these are forms of neurologic damage, including blindness, deafness, and mental retardation. […] For Hib meningitis (the most common form of invasive Hib disease), the case fatality rate is 2-5%.

• #59 Disease information about Invasive Haemophilus influenzae disease

  https://www.ecdc.europa.eu/en/invasive-haemophilus-influenzae-disease/facts

  Haemophilus influenzae serotype b (Hib) is the most common cause of bacterial meningitis in children aged two months to five years, in those countries where suitable vaccination programmes are not in place. […] Haemophilus influenzae type b is an encapsulated, immotile and non-spore forming Gram-negative coccobacillus. […] Serotype b (Hib) has a polyribosyl ribitol phosphate (PRP) polysaccharide capsule that is a major virulence factor. […] The PRP capsule protects the organism from phagocytosis in the absence of anticapsular antibodies and facilitates penetration to the blood stream and the cerebrospinal fluid. […] Haemophilus influenzae type b causes pneumonia, septicaemia, meningitis, epiglottitis, septic arthritis, cellulitis, otitis media, and purulent pericarditis, as well as less common invasive infections such as endocarditis, osteomyelitis, and peritonitis.

• #60 Haemophilus influenzae type b (Hib) | The Australian Immunisation Handbook

  https://immunisationhandbook.health.gov.au/contents/vaccine-preventable-diseases/haemophilus-influenzae-type-b-hib

  Haemophilus influenzae is a bacterium that is a normal part of the upper respiratory tract flora. H. influenzae type b (Hib) can cause invasive diseases in children and in people who are immunocompromised. These diseases include bacterial meningitis, pneumonia, epiglottitis, septic arthritis and cellulitis. […] The incubation period of Hib disease is not definitively known, but is estimated to be 2–4 days. […] Hib can be transmitted from symptomatic or asymptomatic carriers by direct contact with respiratory droplets or nasal discharge. An infected person can transmit Hib disease for as long as the bacteria are present, which may be several months. […] Identification of gram-negative coccobacilli in body fluid suggests Hib disease. Culturing Hib from body fluids can be difficult because the organism needs specific growth media and culturing conditions. […] It is important that all isolates of Hib are serotyped because only type b is vaccine-preventable.

• #61 Pathogen Safety Data Sheets: Infectious Substances – Haemophilus influenzae (type b) – Canada.ca

  https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/haemophilus-influenzae.html

  H. influenzae is a common commensal bacterium of the upper respiratory tract, but it can also cause localized (e.g., infections of the upper and lower respiratory tract, paranasal sinuses, middle ears, conjunctivae, skin) or invasive disease (e.g., meningitis, septicemia, epiglottitis, pneumonia, pericarditis, septic arthritis). […] H. influenzae serotype b (Hib) is the most virulent. […] Hib is more commonly associated with meningitis in children, whereas NTHi is more commonly associated with meningitis in adults. […] Acute epiglottitis infection is associated with capsulated H. influenzae, and is characterized by inflammation of the epiglottis. […] NTHi, Hib, and non-type b capsulated H. influenzae-associated pneumonia affects children and adults. […] Invasive NTHi infection has been associated with early pregnancy loss.

• #62

  https://historyofvaccines.org/diseases/hib-haemophilus-influenzae-type-b/

  Haemophilus Influenzae type b, commonly known as Hib, is a bacterium that can cause severe infections, particularly in young children. Hib bacteria can cause many types of invasive disease, including meningitis, pneumonia, cellulitis (skin infection), septic arthritis (joint infection) and epiglottitis (infection of the epiglottis, causing obstruction or closing of the windpipe). […] Before the Hib vaccine was introduced, meningitis infection of the membranes that cover the brain was the most common Hib-induced invasive disease. […] Because the spectrum of Hib disease ranges from meningitis to pneumonia, the types of complications vary depending on the type of Hib infection. Many of these are forms of neurologic damage, including blindness, deafness, and mental retardation. […] For Hib meningitis (the most common form of invasive Hib disease), the case fatality rate is 2-5%.

• #63

  https://historyofvaccines.org/diseases/hib-haemophilus-influenzae-type-b/

  Haemophilus Influenzae type b, commonly known as Hib, is a bacterium that can cause severe infections, particularly in young children. Hib bacteria can cause many types of invasive disease, including meningitis, pneumonia, cellulitis (skin infection), septic arthritis (joint infection) and epiglottitis (infection of the epiglottis, causing obstruction or closing of the windpipe). […] Before the Hib vaccine was introduced, meningitis infection of the membranes that cover the brain was the most common Hib-induced invasive disease. […] Because the spectrum of Hib disease ranges from meningitis to pneumonia, the types of complications vary depending on the type of Hib infection. Many of these are forms of neurologic damage, including blindness, deafness, and mental retardation. […] For Hib meningitis (the most common form of invasive Hib disease), the case fatality rate is 2-5%.

• #64 Haemophilus Influenzae Type B (Hib): The Disease & Vaccines | Children’s Hospital of Philadelphia

  https://www.chop.edu/vaccine-education-center/vaccine-details/haemophilus-influenzae-type-b-hib-vaccine

  Haemophilus influenzae type b (Hib) is a bacterium that infects the lining of the brain, causing meningitis. Meningitis is caused by several different bacteria. However, before the Hib vaccine, Hib was by far the most common cause of meningitis. […] The Hib vaccine is made from the sugar coating (polysaccharide) of the bacteria. Antibodies directed against the Hib polysaccharide protect the child against an infection that could result in permanent disabilities or death. […] Scientists have figured out that by taking the Hib polysaccharide and linking it to a harmless protein, young children are able to make a stronger immune response to the polysaccharide. This conjugated version of the Hib vaccine works extremely well. […] The Hib vaccine has caused a dramatic decline in the incidence of meningitis, bloodstream infections, and pneumonia caused by Hib. However, Hib bacteria still circulate in the community and occasionally cause disease.

• #65 Hib vaccine | EBSCO Research Starters

  https://www.ebsco.com/research-starters/health-and-medicine/hib-vaccine

  The Hib vaccine is made by taking the shell (the polysaccharide coating) of the Hib bacterium and linking it to another protein. Injection of this safe combination incites the body to produce an immune response against this Hib bacteria coating without actually causing the disease, thus protecting against future infection. […] The Hib vaccine is highly effective at preventing the diseases commonly caused by the bacterium H. influenzae. Before the development of this vaccine, Hib was the leading cause of meningitis in children. It is estimated that the mortality rate among infants and children who contracted this illness was 5 percent, with an even greater incidence of permanent brain damage or hearing loss, or both, among survivors. […] Epiglottitis, a serious disease most commonly caused by Hib, was widespread before Hib vaccination became standard. However, it has virtually disappeared as a disease, and many pediatricians have learned of this illness only by anecdote.

• #66 Hib vaccine | EBSCO Research Starters

  https://www.ebsco.com/research-starters/health-and-medicine/hib-vaccine

  The Hib vaccine is made by taking the shell (the polysaccharide coating) of the Hib bacterium and linking it to another protein. Injection of this safe combination incites the body to produce an immune response against this Hib bacteria coating without actually causing the disease, thus protecting against future infection. […] The Hib vaccine is highly effective at preventing the diseases commonly caused by the bacterium H. influenzae. Before the development of this vaccine, Hib was the leading cause of meningitis in children. It is estimated that the mortality rate among infants and children who contracted this illness was 5 percent, with an even greater incidence of permanent brain damage or hearing loss, or both, among survivors. […] Epiglottitis, a serious disease most commonly caused by Hib, was widespread before Hib vaccination became standard. However, it has virtually disappeared as a disease, and many pediatricians have learned of this illness only by anecdote.

• #67 Haemophilus Influenzae Type B (Hib): The Disease & Vaccines | Children’s Hospital of Philadelphia

  https://www.chop.edu/vaccine-education-center/vaccine-details/haemophilus-influenzae-type-b-hib-vaccine

  Haemophilus influenzae type b (Hib) is a bacterium that infects the lining of the brain, causing meningitis. Meningitis is caused by several different bacteria. However, before the Hib vaccine, Hib was by far the most common cause of meningitis. […] The Hib vaccine is made from the sugar coating (polysaccharide) of the bacteria. Antibodies directed against the Hib polysaccharide protect the child against an infection that could result in permanent disabilities or death. […] Scientists have figured out that by taking the Hib polysaccharide and linking it to a harmless protein, young children are able to make a stronger immune response to the polysaccharide. This conjugated version of the Hib vaccine works extremely well. […] The Hib vaccine has caused a dramatic decline in the incidence of meningitis, bloodstream infections, and pneumonia caused by Hib. However, Hib bacteria still circulate in the community and occasionally cause disease.

• #68 Haemophilus influenzae – Wikipedia

  https://en.wikipedia.org/wiki/Haemophilus_influenzae

  Naturally acquired disease caused by H. influenzaeseems to occur in humans only. […] In healthy children under the age of 5,H. influenzaetype b was responsible for more than 80% of aggressive infections, before the introduction of the [Hib] vaccine. […] In infants and young children,H. influenzaetype b (Hib) causes bacteremia, pneumonia, epiglottitis and acute bacterial meningitis. […] However, Hib remains a major cause of lower respiratory tract infections in infants and children in developing countries where the vaccine is not widely used.

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