Hepatitis B Vaccine May Be Linked to MS
Findings of Threefold Increased Risk Contradict Most Previous Research
A Billion Doses continued...
In the newly published study, researcher Miguel Hernan, MD, used a national health database from the U.K. to identify MS patients and people who had gotten the hepatitis B vaccine. Roughly 3 million Britons were registered in the database, and the researchers included only 163 of more 700 cases of MS patients and 10 times as many people who did not have MS in the analysis.
The researchers estimated that immunization was associated with a threefold increase in MS risk within the three years following vaccination.
Most With MS Weren't Vaccinated
While conceding that the new study was well designed and well executed, University of Washington neurology professor Anne H. Cross, MD, argues that the exclusion of so many MS patients in the analysis could have been a factor in the outcome. Of 713 MS cases identified, the researchers included only 163 in their study and just 11 of these developed first symptoms of MS within three years of vaccination.
"One must consider whether this selection process, which was deemed necessary to properly perform the study, might have led to some unrecognized bias," Cross wrote in an editorial she co-authored.
It makes little sense, she says, that the hepatitis B vaccine causes MS when there is no evidence linking the virus to the disease.
"The vaccine is just a peptide (a small protein) of the virus, so it stands to reason that if there is a link between the vaccine and MS there would also be a link between hepatitis B virus infection and MS," she tells WebMD.
She also pointed out that more than 90% of the multiple sclerosis patients in the database had not been vaccinated against hepatitis B.
The hepatitis B vaccine is now routinely given to infants in the U.S. as a series of shots, and CDC spokesman Eric Mast, MD, MPH, noted that there is no evidence linking the vaccine to MS or any other neurological disease in children.
Mast, who is acting director of the division of viral hepatitis, tells WebMD that even with the addition of the newest study, the clinical evidence does not support a link between the hepatitis B vaccine and MS.
"This has certainly been on our radar screen, and we need to continue to look at it," he says. "But the preponderance of evidence suggests no association."