What Is the Hepatitis A Vaccine?

The hepatitis A vaccine, also called HepA, is an effective way to protect against hepatitis A, a liver infection caused by the hepatitis A virus. The virus spreads mostly through contaminated foods or drinks, as well as through close contact with people who are infected.

Hepatitis A infections can cause symptoms like nausea, vomiting, diarrhea, fever, joint pain, and yellowing of the skin for weeks to months. The hepatitis A vaccine is safe and causes few side effects.

Why Is the Hepatitis A Vaccine Important?

The hepatitis A vaccine, or immunization, helps protect against hepatitis A liver infections, which are very contagious (easy to catch from someone else). Doctors have given the vaccine to millions of people for decades. In fact, it’s part of the routine vaccine schedule.

When you get your child vaccinated with the hepatitis A vaccine, you’re helping prevent the spread of infections caused by the hepatitis A virus, so you’re also protecting other people. This includes babies who are too young to get the vaccine, people who are severely allergic to it, and people with some serious illnesses.

Getting the vaccine also can help prevent outbreaks (when more people get sick with a disease than expected in one area). Childcare centers used to be common sites of hepatitis A infection outbreaks. Many kids who were infected didn’t have symptoms, so they easily spread the virus to others. Now that many young kids are getting vaccinated against hepatitis A infection, such outbreaks are less common. Outbreaks can still happen in other settings, though.

How Does the Hepatitis A Vaccination Work?

The hepatitis A vaccine is given as injections, or shots, which contain a small piece of the hepatitis A virus that’s killed, or inactivated. (The vaccine can’t cause hepatitis A infections.) After someone is given the vaccine, the body’s immune system makes proteins called antibodies, which can spot the virus. These antibodies last a long time in the body. This means that if the person is later exposed to the hepatitis A virus, the antibodies are in place. The body knows how to fight the virus so the person doesn’t get sick. This is called immunity.

When Should My Child Get the Hepatitis A Vaccine?

The hepatitis A vaccine is recommended for children 12–23 months old, who will get a second dose at least 6 months later. Babies as young as 6 months old also can get it if they’ll travel to a place where hepatitis A infections are common. They’ll still need the routine vaccination after their first birthday.

The hepatitis A vaccine is also recommended for all older kids and adults who haven’t already gotten vaccinated, especially if they have a higher risk of:

• being infected, like families who adopt a child from another country
• getting very sick with hepatitis A infection, like people with chronic (long-term) liver disease or HIV infection

Anyone who hasn’t been vaccinated and has direct contact with someone who has hepatitis A infection should get the shot within 2 weeks. This helps avoid getting the infection.

What Are the Possible Side Effects of the Hepatitis A Vaccine?

The hepatitis A vaccine can cause mild side effects that go away after a couple of days, like a low fever, headache, tiredness, loss of appetite, and soreness or redness where the shot was given. As with any vaccine, there’s a small risk of fainting and a very small chance of an allergic reaction.

Caring for Your Child After the Hepatitis A Vaccine

For soreness or fever, check with your doctor to see if you can give either acetaminophen or ibuprofen, and to find out the right dose. Do not give ibuprofen to babies under 6 months unless your doctor tells you to.

A cool, damp cloth or a heating pad at the site of the shot may help reduce soreness, as can moving or using the arm or leg.

When Should I Call the Doctor?

Call your doctor if your child has any symptoms of an allergic reaction (like swelling or redness of the face, or hives) or doesn’t feel well after getting the vaccine.

When to Delay or Avoid the Hepatitis A Vaccine

Kids can still get the hepatitis A vaccine if they have a simple cold or other minor illness. Your doctor might choose to delay the vaccine if your child has a more serious illness.

Talk to your doctor if your child ever had a serious allergic reaction, or any allergic reaction to:

• an earlier hepatitis A shot
• latex

Your doctor may choose not to give the hepatitis A vaccine.