The hepatitis B vaccine (search) works for at least 15 years -- longer than once thought.
The vaccine thwarts the virus that causes hepatitis B, a liver disease that can lead to liver cirrhosis (search) or cancer. Most countries include the vaccine in their infant immunization programs. It’s given in a series of three shots and was known to protect against hepatitis B for five to 10 years. But no one knew if it worked beyond that point.
Now, researchers have an answer. The vaccine “strongly protected against [hepatitis B] infection for at least 15 years in all age groups,” they report.
However, the benefits faded fastest in people vaccinated when they were 4 years old or younger. Researchers will keep an eye on those patients to see if they need additional doses of the vaccine or booster shots in the future.
The news comes from a study of Alaska natives, who have high rates of hepatitis B, with most cases starting in early childhood.
A total of 1,578 people participated.
In the early 1980s, participants were fully vaccinated against hepatitis B. All were at least six months old, and some were in their 20s or older.
After 15 years, the researchers were still in touch with almost half of the group. The vaccine's protection against infection was still going strong in 84 percent of those people.
Vaccine Lasts Longer After 5th Birthday
The vaccine's effectiveness waned the most in people vaccinated before their fifth birthday. “It is important that we continue to follow this group in order to determine when and if booster doses will be necessary,” says the study.
The report comes from researchers including Brian McMahon, MD, of the CDC’s Arctic Investigations Program. The study appears in the March 1 edition of the Annals of Internal Medicine.
The finding may spare patients from needless booster shots, says Ding-Shinn Chen, MD, of National Taiwan University’s medical school.
“Unless continued follow-up and surveillance show clinically significant rates of infection for adolescents who were vaccinated as children, booster vaccinations will be wasteful,” writes Chen in an Annals of Internal Medicine editorial.
Hepatitis B can be spread through contact with infected body fluids, such as through sexual contact or shared needles. It can also be spread from an infected mother to her newborn at the time of birth.
The vaccine is the one of the most effective ways to prevent hepatitis B infection. It's most effective when all three shots of the vaccine are given.
For further protection, use a condom when you have sex, don’t share needles, wear plastic or latex gloves if you have to touch blood, and don’t share toothbrushes or razors.
SOURCES: McMahon, B. Annals of Internal Medicine, March 1, 2005; vol 142: pp 333-341. Chen, D-S. Annals of Internal Medicine, March 1, 2005; vol 142: pp 384-385. WebMD Medical Reference from Healthwise: “Hepatitis B Prevention.”