NEWS Hepatitis B Vaccine May Be Linked to MS

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Hepatitis B Vaccine May Be Linked to MS

Findings of Threefold Increased Risk Contradict Most Previous Research

By Salynn Boyles

WebMD Medical News Reviewed By Brunilda Nazario, MD

on Monday, September 13, 2004

Sept. 13, 2004 --The hepatitis B vaccine series has been administered to

more than 20 million people in the U.S. and more than 500 million people in

the world. It is more than 95% effective in preventing an infection that

kills millions annually. However anecdotal evidence has linked the vaccine

to an increased risk for multiple sclerosis.

Now a new study in the Sept. 14 issue of the journal Neurology offers the

some of the strongest evidence supporting the link.

In the study, researchers report that vaccination with the recombinant

hepatitis B vaccine is associated with a threefold increased risk of

multiple sclerosis.

They concluded that the benefits of the vaccine still appear to outweigh the

risks, but added that the findings " challenge the idea that the relation

between hepatitis B vaccination and the risk of MS is well understood. "

" We aren't policy makers, but it is important to recognize that many lives

are saved by this vaccine, " researcher Jick, DSc, tells WebMD. " We

certainly aren't suggesting that people stop getting vaccinated. But this

study raises important questions. "

The actual cause of MS is still unknown but MS is believed to be an

autoimmune disease in genetically susceptible persons. Reports of hepatitis

B vaccination and MS were from anecdotal case reports, not scientifically

controlled studies.

A Billion Doses

Approximately 350 million people worldwide are infected with hepatitis B

virus, and as many as 65 million will die from liver cancer or cirrhosis of

the liver as a result. The hepatitis B vaccine has generally been considered

one of the safest vaccines ever produced, and more than a billion doses have

been given since was first made available in the early 1980s.

Reports in the mid-1990s pointing to a link between the vaccine and MS lead

the French government to temporarily suspend the routine immunization of

pre-adolescents in schools, but most clinical trials have not supported the

association.

Two years ago an immunization safety committee guided by the Centers for

Disease Control and Prevention and the Institutes of Health reported that

the clinical evidence " favors rejection of a causal relationship between

hepatitis B vaccine and multiple sclerosis. "

In the newly published study, researcher 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 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. "

SOURCES: Hernan, M. Neurology, Sept. 14, 2004; vol 63: pp 772-723.

Jick, DSc, associate professor of epidemiology, Boston School of Public

Health. Anne H. Cross, MD, professor of neurology, Washington University,

St. Louis. Mast, MD, MPH, acting director, division of viral hepatitis,

CDC.

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