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Haemophilus influenzae type B and Hib Vaccine

Haemophilus influenzae type B and Hib Vaccine. Epidemiology and Prevention of Vaccine-Preventable Diseases National Center for Immunization and Respiratory Diseases Centers for Disease Control and Prevention. Revised March 2008. Note to presenters:

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Haemophilus influenzae type B and Hib Vaccine

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  1. Haemophilus influenzae type B and Hib Vaccine Epidemiology and Prevention of Vaccine-Preventable Diseases National Center for Immunization and Respiratory Diseases Centers for Disease Control and Prevention Revised March 2008

  2. Note to presenters: Images of vaccine-preventable diseases are available from the Immunization Action Coalition website at http://www.vaccineinformation.org/photos/index.asp

  3. Haemophilus influenzae type b • Severe bacterial infection, particularly among infants • During late 19th century believed to cause influenza • Immunology and microbiology clarified in 1930s

  4. Haemophilus influenzae • Aerobic gram-negative bacteria • Polysaccharide capsule • Six different serotypes (a-f) of polysaccharide capsule • 95% of invasive disease caused by type b

  5. Haemophilus influenzae type bPathogenesis • Organism colonizes nasopharynx • In some persons organism invades bloodstream and cause infection at distant site • Antecedent upper respiratory tract infection may be a contributing factor

  6. Haemophilus influenzae type b Clinical Features* *prevaccination era

  7. Haemophilus influenzae type b Meningitis • Accounted for approximately 50%-65% of cases in the prevaccine era • Hearing impairment or neurologic sequelae in 15%-30% • Case-fatality rate 2%-5% despite of effective antimicrobial therapy

  8. Haemophilus influenzae type b Medical Management • Hospitalization required • Treatment with an effective 3rd generation cephalosporin, or chloramphenicol plus ampicillin • Ampicillin-resistant strains now common throughout the United States

  9. Haemophilus influenzae type b Epidemiology • Reservoir Human Asymptomatic carriers • Transmission Respiratory droplets • Temporal pattern Peaks in Sept-Dec and March-May • Communicability Generally limited but higher in some circumstances

  10. Incidence*of Invasive Hib Disease, 1990-2005 Year *Rate per 100,000 children <5 years of age

  11. Haemophilus influenzae type b, 1986 Incidence* by Age Group *Rate per 100,000 population, prevaccine era

  12. Haemophilus influenzae type b—United States, 2002-2006 • Incidence has fallen more than 99% since prevaccine era • 123 confirmed Hib cases reported (average of 25 cases per year) • Most recent cases in unvaccinated or incompletely vaccinated children

  13. Haemophilus influenzae type bRisk Factors for Invasive Disease • Exposure factors • household crowding • large household size • child care attendance • low socioeconomic status • low parental education • school-aged siblings • Host factors • race/ethnicity • chronic disease

  14. Haemophilus influenzae type bPolysaccharide Vaccine • Available 1985-1988 • Not effective in children younger than 18 months of age • Effectiveness in older children variable

  15. Polysaccharide Vaccines • Age-related immune response • Not consistently immunogenic in children 2 years of age and younger • No booster response • Antibody with less functional activity

  16. Polysaccharide Conjugate Vaccines • Stimulates T-dependent immunity • Enhanced antibody production, especially in young children • Repeat doses elicit booster response

  17. Haemophilus influenzae type b Conjugate Vaccines • Two conjugate vaccines licensed for use in infants as young as 6 weeks of age • Use different carrier proteins • 3 doses of any combination confers protection

  18. Conjugate Hib Vaccines* PRP-T ActHIB, TriHIBit PRP-OMP PedvaxHIB, Comvax *HbOC (HibTiter) no longer available in the United States

  19. Haemophilus influenzae type b Vaccine Routine Schedule Vaccine 2 mo 4 mo 6 mo 12-18 mo PRP-T x x x x PRP-OMP x x x

  20. Haemophilus influenzae type b Vaccine • Recommended interval 8 weeks for primary series doses • Minimum interval 4 weeks for primary series doses • Vaccination at younger than 6 weeks of age may induce immunologic tolerance to Hib antigen • Minimum age 6 weeks

  21. Haemophilus influenzae type b Vaccine Interchangeability • Both conjugate Hib vaccines (except TriHIBit) are interchangeable for primary series and booster dose • 3 dose primary series if more than one brand of vaccine used

  22. Haemophilus influenzae type b Vaccine Delayed Vaccination Schedule • Unvaccinated children 7 months of age or older may not need entire 3 or 4 dose series • Number of doses child requires depends on current age • All children 15-59 months of age need at least 1 dose

  23. Haemophilus influenzae type b VaccineDetailed Schedule for Unimmunized Children Vaccine Age at 1st Dose (months) Primary series Booster HbOC/PRP-T 2-6 3 doses, 2 m apart 12-15 months 7-11 2 doses, 2 m apart 12-18 months 12-14 1 dose 2 months later 15-59 1 dose -- 2-6 PRP-OMP 2 doses, 2 m apart 12-15 months 7-11 2 doses, 2 m apart 12-18 months 12-14 1 dose 2 months later 15-59 1 dose --

  24. Lapsed Immunization • Children who have fallen behind schedule with Hib vaccine may not need all the remaining doses of a 3 or 4 dose series • The number of doses needed to complete the series should be determined using the catch-up schedule*, published annually with the childhood schedule *available at ww.cdc.gov/vaccines/recs/schedules/child-schedule.htm

  25. Haemophilus influenzae type b VaccineVaccination Following Invasive Disease • Children younger than 24 months may not develop protective antibody after invasive disease • Vaccinate during convalescence • Complete series for age

  26. Haemophilus influenzae type b VaccineUse in Older Children and Adults • Generally not recommended for persons older than 59 months of age • Consider for high-risk persons: asplenia, immunodeficiency, HIV infection • One pediatric dose of any conjugate vaccine • 3 doses recommended for all persons who have received a hematopoietic stem cell transplant

  27. Combination Vaccines Containing Hib • DTaP—Hib • TriHIBit • Hepatitis B—Hib • Comvax

  28. TriHIBit • ActHIB reconstituted with Tripedia • Not approved for the primary series at 2, 4, or 6 months of age • Approved for the fourth dose of the DTaP and Hib series only • Primary series Hib doses given as TriHIBit should be disregarded

  29. TriHIBit • May be used as the booster dose of the Hib series at 12 months of age or older following any Hib vaccine series* • Should not be used if child has receive no prior Hib doses *booster dose should follow prior dose by at least 2 months

  30. Comvax • Hepatitis B-Hib combination • Use when either or both antigens indicated at 6 weeks of age or older • Not licensed for use if mother HBsAg+ • Spacing and timing rules same as for individual antigens

  31. Comvax Minimum Intervals • Package insert implies 8 to 11-month interval between doses 2 and 3 • This applies only if dose 2 given at 4 months of age • Minimum interval if not on schedule is TWO months (minumum age 12 months)

  32. Hib Vaccination Recommendations During the Current Shortage • The booster dose of Hib vaccine usually administered at 12-15 months of age should be deferred except for children at increased risk of Hib disease • asplenia • sickle cell disease • immunodeficiency (including HIV infection and cancer) • American Indian/Alaska Native children MMWR 2007; 56(50);1318-1320

  33. Haemophilus influenzae type b Vaccine Adverse Reactions • Swelling, redness, or pain in 5%-30% of recipients • Systemic reactions infrequent • Serious adverse reactions rare

  34. Haemophilus influenzae type b Vaccine Contraindications and Precautions • Severe allergic reaction to vaccine component or following a prior dose • Moderate or severe acute illness • Age less than 6 weeks

  35. CDC Vaccines and ImmunizationContact Information • Telephone 800.CDC.INFO • Email nipinfo@cdc.gov • Website www.cdc.gov/vaccines

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