Does Hepatitis B Vaccination Protection Continue after 15 Years?

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The summary below is from the full report titled "Antibody Levels and Protection after Hepatitis B Vaccination: Results of a 15-Year Follow-up." It is in the 1 March 2005 issue of Annals of Internal Medicine (volume 142, pages 333-341). The authors are B.J. McMahon, D.L. Bruden, K.M. Petersen, L.R. Bulkow, A.J. Parkinson, O. Nainan, M. Khristova, C. Zanis, H. Peters, and H.S. Margolis.

What is the problem and what is known about it so far?

Hepatitis B virus causes inflammation of the liver. The virus spreads through contact with infected body fluids, such as through sexual intercourse, open cuts, or scratches, or from mother to baby at birth. Most people do not realize that they have been infected until chronic inflammation causes complications, such as liver scarring or cancer. A hepatitis B vaccine can boost the body's immune response to the virus and help protect against infection. The vaccine is recommended for people at high risk for infection. Some research shows that the vaccine protects against infection for up to 10 years. It is not known whether the protection lasts longer than 10 years.

Why did the researchers do this particular study?

To see whether the hepatitis B vaccine protects against infection for up to 15 years.

Who was studied?

841 Alaska Natives vaccinated with the hepatitis B vaccine beginning in 1981. Hepatitis B virus infection is common in Alaska Native communities, so members of those communities are especially likely to benefit from vaccination.

How was the study done?

The researchers took blood from participants and measured hepatitis B antibodies and hepatitis B virus DNA 15 years after vaccination. They used the results to see whether the vaccine protected participants from infection and to see whether any participants developed a new infection.

What did the researchers find?

The researchers found protective antibodies in 84% of the participants 15 years after vaccination. Protection from infection was more likely in men, people who had a good initial response to the vaccine, and people vaccinated when they were 5 years of age or older. Three participants became newly infected with hepatitis B virus 10 to 15 years after vaccination.

What are the limitations of the study?

The findings may be incomplete because about half of the vaccinated participants were not available for testing 15 years later.

What are the implications of the study?

The hepatitis B vaccine protected most participants from infection and all participants from complications of infection for at least 15 years. People younger than age 5 at the time of vaccination may be less well protected and might benefit from booster doses of vaccine.