Hepatitis B: What Parents Should Know

When thinking about vaccines and children’s health, it’s understandable to focus on illnesses like measles, whooping cough, or influenza. But there’s one virus that often doesn’t get as much attention, despite its potential for serious long-term effects, and that is hepatitis B (HBV). In this blog, we share what hepatitis B is, how it spreads, and how vaccination protects your child.

Hepatitis B is a virus that affects the liver, an essential organ that helps with digestion, filtering toxins, and storing energy. The hepatitis B virus can cause both short-term (acute) and long-term (chronic) infections. For some people, especially adults, the immune system clears the virus naturally. For others, particularly infants and young children, the infection can become chronic. Over time, chronic hepatitis B can lead to serious complications, such as liver disease, liver failure, or even liver cancer.

Hepatitis B spreads through contact with infected blood or body fluids. In adults, this can happen through unprotected sex or sharing needles. In babies and young children, the most common risk is transmission from an infected mother at birth or exposure in the hospital. However, in the U.S., routine vaccination programs have dramatically reduced the number of people who get hepatitis B. This has led to a nearly 90% decrease in hepatitis B infections.

Because infants are at the highest risk of developing chronic infection if exposed, it is recommended to begin Hepatitis B vaccination early, often within the first 24 hours after birth. The American Academy of Pediatrics (AAP) strongly supports giving the first dose of the hepatitis B vaccine in the hospital after delivery, unless there’s a specific medical reason not to. Starting vaccination right away helps protect babies from acquiring the virus at birth or shortly afterward. This early protection is important because babies and young children are more likely than adults to develop lifelong infection if exposed. In fact, around 90% of infants infected with hepatitis B at birth go on to develop chronic disease unless they are protected by vaccination. That’s why the first dose of the vaccine is recommended so soon after birth, as it dramatically reduces the chances of transmission and long-term health problems.

The hepatitis B vaccine is both safe and effective. It helps the body build immunity against the virus without causing the disease itself. The vaccine contains a tiny piece of the virus (not the live virus), which prompts the immune system to respond and remember how to fight it if exposed in the future. The typical vaccination schedule begins with a dose shortly after birth, ideally within the first 24 hours. Subsequent doses are given at intervals during infancy and early childhood to ensure strong, lasting protection. The vaccine is usually combined with other routine infant immunizations so that children are fully protected before they begin school.

Parents often ask about vaccine safety, and it’s natural to want reassurance. Decades of research and monitoring show that the hepatitis B vaccine is safe. Most side effects, if they occur, are mild, such as soreness at the injection site, mild fever, or fussiness. Serious side effects are extremely rare. Because the vaccine does not contain the live virus, it cannot cause hepatitis B. What it does do is give a young child’s immune system the information it needs to protect the liver from the virus. This is especially important for infants whose developing bodies are particularly vulnerable to chronic infection.

The hepatitis B vaccine has been part of childhood immunization programs in the U.S. for many years, and since then, rates of new Hepatitis B infections have dropped significantly. That means fewer children are at risk of chronic infection and its serious consequences later in life. Giving your baby the hepatitis B vaccine on schedule helps them build strong defenses before they are vulnerable. 

If you have questions about the hepatitis B vaccine, your pediatrician is the best source of trusted answers. We can guide you through the immunization schedule, address concerns, and help you make informed decisions that support your child’s long-term health.