What is the Hepatitis B Vaccine and Who Needs It? The Answer May Surprise You

The routine vaccine that prevents a serious liver infection is commonly given at birth — but it’s not just for babies

Rachel Nania,

AARP

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Published September 18, 2025

AARP (Getty Images)

Nearly all babies in the U.S. get a hepatitis B vaccine at birth — a 30-plus-year practice that could be reconsidered following a Sept. 18 vote by a key federal advisory panel. Since then, rates of the serious liver infection have plummeted among children and adolescents.

“This strategy has been brilliantly successful,” says Dr. William Schaffner, an infectious disease specialist and professor of preventive medicine at Vanderbilt University School of Medicine.

But it’s not just little ones who need the vaccine. In 2022, the Centers for Disease Control and Prevention (CDC) updated its guidelines to recommend the vaccine for all adults ages 19 to 59 and for many people 60 and older who are at higher risk of contracting the virus.

Still, only about one-third of adults age 19 and older have received the vaccine, according to federal data. One possible reason for the low uptake is a lack of awareness.

“I think partially, it’s just a disease that is not as visible,” says David W. Hutton, professor of health management and policy at the University of Michigan’s School of Public Health. “It’s an infection we don’t talk a lot about in the U.S.”

But as many as 2.4 million people in the U.S. are living with chronic hepatitis B, the Hepatitis B Foundation says, and each year, around 14,000 new cases are reported. Here’s what you need to know about the vaccine and the disease it helps prevent.

What is hepatitis B?

Hepatitis B is a liver disease caused by the hepatitis B virus.

The virus can cause an acute infection that can make you sick enough to be put in the hospital, Schaffner says. In 2023, nearly half of all acute hepatitis B cases were among people ages 40 to 59, according to the CDC.

“It can also induce a smoldering infection that goes on undetected,” Schaffner says. “You feel perfectly fine, but the virus is slowly multiplying in the liver, causing slow damage such that, over the years, the body responds by putting fibrous tissue in that liver. And what that can result in is cirrhosis, or really severe liver damage down the road.”

In some instances, hepatitis B can lead to liver cancer. In fact, it’s the leading cause of liver cancer worldwide. “So the hepatitis B vaccine was actually our first anticancer vaccine,” Schaffner says.

What are the symptoms of hepatitis B?

Many people do not develop symptoms, and some experience mild symptoms that are similar to other common illnesses. Because of this, they may not know they are infected. In fact, about half of people with hepatitis B do not know they have it, according to the CDC.

Symptoms of acute and chronic infections can be similar; the key distinction is that chronic infections can take decades to develop. Hepatitis B symptoms can include:

Dark urine or clay-colored stools
Feeling tired
Fever
Joint pain
Loss of appetite
Nausea, stomach pain, throwing up
Yellow skin or eyes (jaundice)

How does it spread?

Hepatitis B is primarily spread through blood, semen or certain other body fluids — even in microscopic amounts, the CDC says.

This is one reason the vaccine is recommended for people with diabetes.

“Diabetics can be at higher risk if they share devices that are used to test their blood sugar with others, or if the devices are shared between people without appropriate disinfection by their medical care providers,” Schaffner says.

“There have been outbreaks of hepatitis in senior citizen centers and nursing homes because providers were not meticulous in disinfecting those glucometers, those devices that measure blood glucose,” he adds.

People who are on dialysis, are sexually active and not in long-term monogamous relationships, and who work in health care facilities and are exposed to blood and other fluids are also considered at higher risk for hepatitis B.

The virus can also be transmitted by sharing personal care items such as toothbrushes, razors or nail clippers, public health officials say.

What is the hepatitis B vaccine?

The hepatitis B vaccines — there are several licensed in the U.S. — “are among our safest and most effective vaccines,” Schaffner says. “And they provide protection of very long duration.”

Depending on the brand, the vaccine is given in two or three doses. If you get the three-shot series, your doctor will give them over a period of six months. The two-dose series is given about one month apart, according to the CDC.

Most people don’t experience any side effects after getting the shot, the CDC says, and for those who do, soreness at the injection site is the most common side effect.

“It’s a very easy vaccine to take, so you don’t really get much feedback from your patients when you inject it or in the days afterward,” Schaffner says.

Medicare Part B covers the hepatitis B vaccine for people who have never received a complete series of shots or who don’t know their vaccination history, and for people with any condition that puts them at risk for hepatitis B. It’s also usually covered by private insurance plans, according to the CDC.

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