Hepatitis B Vaccine Linked to MS
A new study from Harvard researchers in Boston suggests a link between the hepatitis B vaccination and multiple sclerosis.
In their study, people who received the vaccine were three-times more likely to develop MS over the next three years than those who were not vaccinated.
While this finding is disturbing, the investigators emphasize the overall effect of the vaccine on the development of MS was small — 93 percent of MS patients in the study had not received the vaccination. They say the benefits of the vaccine far outweigh the potential risk. Specifically, the hepatitis B vaccine is more than 95-percent effective in preventing chronic hepatitis B infection. It is also effective in preventing against liver cancer, making it the first vaccine to ever protect against a major form of cancer in humans. It is considered one of the safest vaccines ever produced.
The researchers also emphasize they cannot be sure whether the vaccine actually caused people to develop MS or just accelerated the disease process in people who would eventually have developed it. Study author Miguel Hernan, M.D., Dr.PH., says, “Our study cannot distinguish whether the vaccine hastens the onset of MS in persons destined to develop the disease years later, or whether it causes new cases of MS in susceptible individuals.”
Dr. Hernan and his colleagues call for more study to find out how the vaccine might be impacting the development of MS.
The study was conducted using a large medical database in the United Kingdom that tracks a wide range of health-related factors for about 5 percent of the population.
SOURCE: Neurology, 2004;63:838-842