The 2019 case definition for acute hepatitis A:*
Clinical Criteria
Laboratory Criteria for Diagnosis
Confirmatory laboratory evidence:
Case Classification – Confirmed
*Per the Council of State and Territorial Epidemiologists (CSTE)
†And not otherwise ruled out by IgM anti-HAV or NAAT for hepatitis A virus testing performed in a public health laboratory
Hepatitis A is transmitted through the fecal-oral route. This can happen through:
Although viremia occurs early in infection, current data indicate that bloodborne transmission of hepatitis A virus is uncommon.
Among older children and adults, infection is typically symptomatic. Symptoms usually occur abruptly and can include the following:
Most (70%) of infections in children younger than age 6 are not accompanied by symptoms. When symptoms are present, young children typically do not have jaundice; most (>70%) older children and adults with HAV infection have this symptom.
Symptoms of hepatitis A usually last less than 2 months, although 10%–15% of symptomatic persons have prolonged or relapsing disease for up to 6 months.
The average incubation period for HAV is 28 days (range: 15–50 days).
HAV can live outside the body for months, depending on the environmental conditions.
In contaminated food, HAV is killed when exposed to temperatures of >185 degrees F (>85 degrees C) for 1 minute. However, the virus can still be spread from cooked food that is contaminated after cooking. Freezing does not inactivate HAV.
Adequate chlorination of water, as recommended, kills HAV that enters the municipal water supply. Transmission of HAV from exposure to contaminated water is rare.
No. Hepatitis A does not become a chronic, long-term, infection.
No. Immunoglobulin G antibodies to the hepatitis A virus, which appear early in the course of infection, provide lifelong protection against the disease.
Vaccination with the full, two-dose series of hepatitis A vaccine is the best way to prevent infection.
Immune globulin can provide short-term protection against hepatitis A, both pre- and postexposure. Immune globulin must be administered within 2 weeks after exposure for maximum protection. Additional guidance is available in MMWR: Updated Dosing Instructions for Immune Globulin (Human) GamaSTAN S/D for Hepatitis A Virus Prophylaxis. Given that the virus is transmitted through the fecal-oral route, good hand hygiene—including handwashing after using the bathroom, changing diapers, and before preparing or eating food—is integral to hepatitis A prevention.
It is recomended that the following people be vaccinated against hepatitis A:
Children
People at increased risk for HAV infection
People at increased risk for severe disease from HAV infection
Other people recommended for vaccination
Vaccination during outbreaks
Implementation strategies for settings providing services to adults
Hepatitis A vaccination is no longer recommended by ACIP
Although no known harm is associated with giving hepatitis A vaccine to infants, the hepatitis A vaccine dose(s) administered prior to 12 months of age might result in a suboptimal immune response, particularly in infants with passively acquired maternal antibody. Therefore, hepatitis A vaccine dose(s) administered at <12 months of age are not considered valid doses.
The two-dose hepatitis A vaccine series should be initiated when the child is at least 1 year of age.
For detailed information on hepatitis A vaccine schedules.
The exact duration of protection against hepatitis A virus infection after vaccination is unknown. Anti-HAV has been shown to persist for at least 20 years in most people receiving the 2-dose series as infants <2 years of age, those vaccinated with a 3-dose series as young children (aged 3-6 years), and adults receiving the entire vaccine series during adulthood.
Yes. Hepatitis B, diphtheria, poliovirus (oral and inactivated), tetanus, typhoid (oral and intramuscular), cholera, Japanese encephalitis, rabies, and yellow fever vaccines can be given at the same time that hepatitis A vaccine is given. In studies among young children, simultaneous administration of hepatitis A vaccine did not affect the immunogenicity or reactogenicity of diphtheria-tetanus-acellular pertussis; inactivated polio; measles, mumps, rubella (MMR); hepatitis B; and Haemophilus influenzae type b vaccines.
Ideally, doses of vaccine in a series come from the same manufacturer; however, if this is not possible or if the manufacturer of doses given previously is unknown, providers should administer the vaccine that they have available. The dose should be considered valid and does not need to be repeated.
The second dose should be given as soon as possible. Even if the second dose is delayed, the first dose does not need to be repeated.
Yes. Pregnant women should be vaccinated for the same indications as non-pregnant women. Unvaccinated or partially vaccinated pregnant adolescents should receive catch-up hepatitis A vaccination. Pregnant women at risk for hepatitis A during pregnancy should also be counseled concerning all options for preventing infection.