# Presentation: 810983

## 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 March 2008**

## Note to presenters:

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

## Hepatitis A

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

## Hepatitis A Virus

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

## 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**

## 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**

## Hepatitis A Epidemiology

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

## Hepatitis A—United States, 1990-2000

**Hepatitis A—United States, 1990-2000**
**Risk Factors**

**Source:  NNDSS/VHSP**

**Notes:**
From 1990 through 2000, the most frequently reported source of infection was personal contact (household or sex) with an infected person (14%).  Two percent of cases involved a child or employee in day-care; 6% of cases were a contact of a child or employee in day-care; 5% of cases reported recent international travel; and 4% of cases reported being part of a recognized foodborne outbreak. Injection drug use was a reported risk factor in 6% of cases; men who have sex with men represented 10% of cases.  Forty-six percent of reported hepatitis A cases could not identify a risk factor for their infection. 
Note: Risk factor percentages rounded to nearest percent

## Hepatitis A - United States, 1966-2006

**Vaccine**
**Licensed**

**Year**

## Hepatitis A Incidence By Age Group, 1990-2004

**Year**

## Hepatitis A Incidence By Vaccination Recommendation Status 1990-2004

**Year**

## Hepatitis A Vaccines

**Inactivated whole virus**
**HAVRIX  (GlaxoSmithKline)**
**VAQTA (Merck)**
**Both vaccines approved for persons 12 months of age and older**
**Pediatric (12 months through 18 years) and adult (19 years and older) formulations**

## Hepatitis A Vaccine Immunogenicity

**Adults**
**>95% seropositive after one dose**
**100% seropositive after two doses**
**Children (>12 months) and Adolescents**
**>97% seropositive after one**
**100% seropositive after 2 doses**

## 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**

## 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%**

## Hepatitis A Vaccines

**Formulation**
_**Pediatric**_
**age**
**dose**
_**Adult**_**      **
**age**
**dose**

**HAVRIX**
**1-18 yrs**
**0.5 ml**
**>18 yrs**
**1.0 ml**

**VAQTA**
**1-18 yrs**
**0.5 ml**
**>18 yrs**
**1.0 ml**

## 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***** 2006;55(No.RR-7):1-23**

## 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***** 2006;55(No.RR-7):1-23**

## 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***** 2006;55(No.RR-7):1-23**

## 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**

## Hepatitis A VaccineInternational 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***** 2007;56(No.41):1080-4**

## 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***** 2007;56(No.41):1080-4**

## 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**

## 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**

## 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**

## 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**

## Schedules That Include BothTwinrix 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**

## Hepatitis A Serologic Testing

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

## Hepatitis A VaccineAdverse Reactions

**Local reaction****	****	****	****	****20%-50%**
**Systemic reactions**
**  ****(malaise, fatigue)****	****	****	****<10%**
**No serious adverse**
**  ****reactions reported**

## Hepatitis A VaccineContraindications and Precautions

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

## CDC Vaccines and ImmunizationContact Information  

**Telephone     800.CDC.INFO**** **
**Email****	****	****    nipinfo@cdc.gov**** **
**Website****	****    www.cdc.gov/vaccines**