# Presentation: 376157

## Hepatitis A and Hepatitis A Vaccine

**Epidemiology and Prevention of Vaccine-Preventable Diseases**
**National Immunization Program**
**Centers for Disease Control and Prevention**

**Revised January 2007**
**Updated April 2007**

## 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, 1966-2005

**Year**

## Hepatitis A Incidence, 1997 

**Hepatitis A Incidence, 1997 **

***rate per 100,000 population**

**Notes:**
This graph shows the incidence of reported hepatitis A by age group in 1997.  The rates are expressed as cases per 100,000 population.  The highest incidence of hepatitis A infection was among children 5 to 14 years of age.  This age group accounted for about 18% of reported cases.  Notice that the incidence of reported hepatitis in children younger than 5 years of age was substantially less than in older children.  Cases in this age group are under-reported because most infections in young children are asymptomatic.

Since 1997, rates among children have declined more rapidly than among adults and in 2001...

## Hepatitis A
High and Intermediate Incidence States, 1999

**High and Intermediate Incidence States, 1999**

**Notes:**
The 6 states in this category are shown in orange.  These states accounted for about 12% of the US population and 18% of reported hepatitis A cases during 1987 through 1997.  Each of the lower incidence states (in blue) should decide whether to adopt a statewide or a community-based vaccination strategy.

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

**Year**

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

**Year**

## Hepatitis A Vaccines

**Inactivated whole virus**
**HAVRIX  (GlaxoSmithKline)**
**VAQTA (Merck)**
**Pediatric and adult formulations**
**Licensed for persons 12 months of age and older**

## Hepatitis A Vaccine Immunogenicity

**>95% seropositive after one dose**
**100% seropositive after two doses**** **
**>97% seropositive after one**
**100% seropositive after 2 doses**

- Adults

- Children** (**_**>**_**12 months) and Adolescents**

## Hepatitis A Vaccine Efficacy

**- 40,000 Thai children 1-16 years of age**
**- vaccine efficacy 94%**
**- 1,000 New York children 2-16 years of age **
**- vaccine efficacy 100%**

- HAVRIX

- VAQTA

## 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 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**

## Hepatitis A Vaccines

**- 1 dose**
**- booster dose 6-18 months after first dose**
**- 1 dose**
**- booster dose 6-18 months after first dose**

- Adult

- Children and Adolescent

## Hepatitis A VaccineMinimum Interval

**The minimum interval between the first and booster doses of hepatitis A vaccine is six calendar months **

## Twinrix

**Combination hepatitis A vaccine (pediatric dose) and hepatitis B (adult dose) **
**Schedule: 0, 1, 6 months***
**Approved for persons 18 years of age and older**

***An alternative Twinrix schedule of 0, 7, 21-30 days and 12 months was approved by FDA in April 2007. See package insert for details.**

## 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 Vaccine Recommendations

**Travelers to high- or intermediate-  risk countries**
**Protected by 4 weeks after dose**
**For optimal protection persons traveling to an area in which risk is high less than 4 weeks after the initial dose also may be administered immune globulin **

## Hepatitis A VaccineInternational Travel

**Protection following hepatitis A vaccine might not be complete until 4 weeks after vaccination**
**For optimal protection immune globulin also may be administered to persons traveling to a high-risk area <4 weeks after the first dose of vaccine **
**Children younger than 12 months of age should receive IG prior to travel to high-risk area **

## Hepatitis A Vaccine Recommendations

**International travelers**
**Men who have sex with men**
**Persons who use illegal drugs**
**Persons who have clotting-factor disorders**
**Persons with occupational risk**
**Persons with chronic liver disease**

## 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**

## 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

**Pain at injection site**
**Systemic reactions not common**
**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**** **

## National Immunization ProgramContact Information

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