Hepatitis A and Hepatitis A Vaccine

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• Hepatitis A and Hepatitis A Vaccine

Epidemiology and Prevention of Vaccine-Preventable
Diseases National Center for Immunization and
Respiratory Diseases Centers for Disease Control
and Prevention
Revised May 2009
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Note to presenters Images of vaccine-preventable
diseases are available from the Immunization
Action Coalition website at http//www.vaccineinfo
rmation.org/photos/index.asp
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Hepatitis A

• Epidemic jaundice described by Hippocrates
• Differentiated from hepatitis B in 1940s
• Serologic tests developed in 1970s
• Vaccines licensed in 1995 and 1996

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Hepatitis A Virus

• Picornavirus (RNA)
• Humans are only natural host
• Stable at low pH
• Inactivated by high temperature (185F or
  higher), formalin, chlorine

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Hepatitis A Pathogenesis

• Entry into mouth
• Viral replication in the liver
• Virus present in blood and feces 10-12 days after
  infection
• Virus excretion may continue for up to 3 weeks
  after onset of symptoms

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Hepatitis A Clinical Features

• Incubation period 28 days (range 15-50 days)
• Illness not specific for hepatitis A
• Likelihood of symptomatic illness directly
  related to age
• Children generally asymptomatic, adults
  symptomatic

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Hepatitis A Epidemiology

• Reservoir Human
• Transmission Fecal-oral
• Temporal pattern None
• Communicability 2 weeks before to 1 week
  after onset

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Hepatitis AUnited States, 1990-2000 Risk Factors
Source NNDSS/VHSP
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• Hepatitis A - United States, 1966-2007

Vaccine Licensed
Year
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Hepatitis A Incidence By Age Group, 1990-2004
Year
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Hepatitis A Incidence By Vaccination
Recommendation Status 1990-2004
Year
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Hepatitis A Vaccines

• Inactivated whole virus vaccines
• Pediatric and adult formulations
• Pediatric formulations vaccines approved for
  persons 12 months through 18 years
• Adult formulations approved for persons 19 years
  and older

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Hepatitis A Vaccine Immunogenicity

• Adults
• gt95 seropositive after one dose
• 100 seropositive after two doses
• Children (gt12 months) and Adolescents
• gt97 seropositive after one
• 100 seropositive after 2 doses

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Hepatitis A Vaccines

• Adult
• 1 dose
• booster dose 6-18 months after first dose
• Children and Adolescents
• 1 dose
• booster dose 6-18 months after first dose

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Hepatitis A Vaccine Efficacy

• HAVRIX
• 40,000 Thai children 1-16 years of age
• vaccine efficacy 94
• VAQTA
• 1,000 New York children 2-16 years of age
• vaccine efficacy 100

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• Hepatitis A Vaccines

Formulation Pediatric age dose Adult
age dose
HAVRIX 1-18 yrs 0.5 ml gt19 yrs 1.0 ml
VAQTA 1-18 yrs 0.5 ml gt19 yrs 1.0 ml
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ACIP Recommendation for Routine Hepatitis A
Vaccination of Children

• All children should receive hepatitis A vaccine
  at 12-23 months of age
• Vaccination should be integrated into the routine
  childhood vaccination schedule
• Children who are not vaccinated by 2 years of age
  can be vaccinated at subsequent visits

MMWR 200655(No.RR-7)1-23
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ACIP Recommendation for Routine Hepatitis A
Vaccination of Children

• States, counties, and communities with existing
  hepatitis A vaccination programs for children 2
  through 18 years of age should maintain these
  programs
• New efforts focused on routine vaccination of
  children 12 months of age should enhance, not
  replace ongoing vaccination programs for older
  children

MMWR 200655(No.RR-7)1-23
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ACIP Recommendation for Routine Hepatitis A
Vaccination of Children

• In areas with without an existing hepatitis A
  vaccination program catch-up vaccination of
  unvaccinated children 2 through 18 years of age
  can be considered

MMWR 200655(No.RR-7)1-23
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Hepatitis A Vaccine Recommendations

• International travelers
• Men who have sex with men
• Persons who use illegal drugs
• Persons with occupational risk
• Persons with chronic liver disease

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Hepatitis A VaccineInternational Travel

• The first dose of hepatitis A vaccine should be
  administered as soon as travel is considered
• For healthy persons 40 years of age or younger
• 1 dose of single-antigen vaccine administered at
  any time before departure
• Persons at risk of severe disease from hepatitis
  A virus planning to travel in 2 weeks or sooner
  should receive the first dose of vaccine and also
  can be administered immune globulin

MMWR 200756(No.41)1080-4
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Hepatitis A Postexposure Prophylaxis

• For healthy persons 12 months through 40 years of
  age
• single-antigen hepatitis A vaccine should be
  administered as soon as possible after exposure
• For persons older than 40 years
• immune globulin is preferred
• vaccine can be used if IG cannot be obtained

MMWR 200756(No.41)1080-4
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Hepatitis A Vaccine Recommendations

• Healthcare workers not routinely recommended
• Child care centers not routinely recommended
• Sewer workers or plumbers not routinely
  recommended
• Food handlers may be considered based on local
  circumstances

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Twinrix

• Combination hepatitis A vaccine (pediatric dose)
  and hepatitis B (adult dose)
• Schedules
• 0, 1, 6 months, or
• 0, 7, 21- 30 days and a booster dose at 12 months
• Approved for persons 18 years of age and older

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New Twinrix Schedule

• Doses at 0, 7, 21- 30 days and a booster dose at
  12 months
• ACIP has no recommendation regarding the new
  schedule
• The first 3 doses of the new schedule provide
  equivalent protection to
• the first dose in the standard single-antigen
  adult hepatitis A vaccine series
• the first 2 doses in the standard adult hepatitis
  B vaccine series

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New Twinrix Schedule

• Seroconversion is nearly 100 after either 3
  doses of Twinrix on the new schedule or a single
  dose of single-antigen adult hepatitis A vaccine
• No increased benefit of the new schedule for the
  hepatitis B component compared to administration
  of 2 hepatitis B vaccine doses 1 to 2 months apart

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Schedules That Include BothTwinrix and Hepatitis
A Vaccine

• Adult formulation single antigen hepatitis A
  vaccine may be used to complete a schedule begun
  with Twinrix and vice versa
• Acceptable schedules
• 2 Twinrix and 1 hepatitis A (adult formulation
• 1 Twinrix and 2 hepatitis A (adult formulation)
• Maintain spacing recommended for Twinrix

for persons 19 years of age or older
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Hepatitis A Serologic Testing

• Prevaccination
• not indicated for children
• may be considered for some adults and older
  adolescent
• Postvaccination
• not indicated

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Hepatitis A VaccineAdverse Reactions

• Local reaction 20-50
• Systemic reactions
• (malaise, fatigue) lt10
• No serious adverse
• reactions attributed to
• vaccine

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Hepatitis A VaccineContraindications and
Precautions

• Severe allergic reaction to a vaccine component
  or following a prior dose
• Moderate or severe acute illness

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CDC Vaccines and ImmunizationContact Information

• Telephone 800.CDC.INFO
• Email nipinfo_at_cdc.gov
• Website www.cdc.gov/vaccines