Hepatitis A is a highly contagious viral infection that affects the liver. Although it usually causes a temporary illness and most people recover completely, it remains an important public health concern because it spreads easily through contaminated food, water, and close personal contact. Fortunately, hepatitis A is preventable through good hygiene practices and effective vaccination.
Here’s what you should know about hepatitis A, including how it spreads, who is at risk, and the current vaccination recommendations.
Hepatitis A is caused by the Hepatitis A virus (HAV), a small RNA virus that infects liver cells.
After entering the body, the virus travels to the liver where it multiplies. It is then released into bile and eventually excreted in the stool, allowing it to spread to other people through the fecal-oral route.
Unlike hepatitis B or hepatitis C, hepatitis A does not cause chronic infection. Most people recover completely, and a previous infection provides lifelong immunity.
The primary method of transmission in the United States is the fecal-oral route, meaning the virus is spread when microscopic amounts of infected stool are ingested.
Common sources of infection include:
One of the reasons hepatitis A spreads so easily is that infected individuals are most contagious before they realize they are sick.
The highest level of infectivity occurs during the two weeks before jaundice develops or liver enzyme levels become elevated, when the concentration of virus in the stool is greatest.
Most hepatitis A infections are self-limiting, meaning the illness resolves on its own without causing permanent liver damage.
Unlike hepatitis B and hepatitis C:
Although deaths are uncommon, hepatitis A can become much more serious in individuals who already have liver disease.
People with chronic hepatitis B, chronic hepatitis C, fatty liver disease, or other chronic liver conditions may experience rapid deterioration of liver function if they become infected with hepatitis A.
Because hepatitis A can survive in the environment, proper food preparation and disinfection are important preventive measures.
The virus can be inactivated by:
Good handwashing with soap and water remains one of the most effective ways to prevent transmission.
The epidemiology of hepatitis A varies around the world.
In many developing nations, most children are infected by 5 years of age. Interestingly, more than 70% of infected children younger than six years experience few or no symptoms.
In North America, hepatitis A occurs more frequently in adults. Individuals between 20 and 39 years of age account for nearly half of reported cases.
Nearly 50% of hepatitis A cases in the United States have no clearly identified risk factor, highlighting how easily the virus can spread in the community.
Certain populations have a greater likelihood of acquiring hepatitis A and are strongly encouraged to receive vaccination.
These include:
Several occupations also carry an increased risk of exposure, including:
Another important group includes family members and caregivers of children adopted internationally from countries where hepatitis A is common. Vaccination is recommended at least two weeks before the child’s arrival, particularly during the first 60 days after arrival, when exposure risk is highest.
The hepatitis A vaccine is one of the safest and most effective methods of preventing infection.
The vaccine contains inactivated (non-live) virus, meaning it cannot cause hepatitis A infection. It is generally well tolerated and is associated with very few systemic side effects.
The Advisory Committee on Immunization Practices (ACIP) recommends routine hepatitis A vaccination for all children beginning at one year of age.
In addition, any person who wishes to be protected against hepatitis A can receive the vaccine, even if they are not in a high-risk group.
If someone has been exposed to hepatitis A, prompt treatment can help prevent infection.
Post-exposure prophylaxis (PEP) should be given within two weeks of exposure for maximum effectiveness.
Two options are available:
Although the vaccine is appropriate for many people, immune globulin is preferred for certain high-risk individuals, including:
If immune globulin is unavailable, the hepatitis A vaccine may be used instead, provided there are no contraindications.
