By Stephanie Nano
Associated Press Writer
Wednesday, January 31, 2001; 5:00 PM
Can a hepatitis B shot cause multiple sclerosis? Despite a lack of scientific evidence, fears of such a link have worried some doctors, parents and patients for years.
Now researchers say there is nothing to worry about.
The vaccine that protects against liver disease doesn't cause multiple sclerosis in healthy people, and doesn't trigger flare-ups in MS patients, according to two studies in Thursday's New England Journal of Medicine.
"I think with the evidence we have now, it is safe, as safe as any other vaccines," said Dr. Alberto Ascherio of Harvard School of Public Health, who led one of the studies. "I don't see why it shouldn't be continued."
Hepatitis B is a potentially deadly virus that can lead to cirrhosis and liver cancer. It is transmitted through blood, bodily fluids, shared needles and from mother to child. The Centers for Disease Control and Prevention estimates 1.25 million Americans have chronic hepatitis B infections.
The hepatitis B vaccine, available since 1982, has been recommended for infants since 1991, and most states require vaccination before children start school. An estimated 20 million Americans have gotten the shots, including health care workers.
Yet questions have lingered about its safety.
An article in the New England Journal of Medicine in September warned that doctors should give the shots only to MS patients who are at substantial risk of exposure because of reports that the vaccine may trigger MS.
In 1998, the French government halted a major vaccination program because of fears that the shots cause neurological disorders, including multiple sclerosis.
That decision prompted the research reported Thursday. Both studies were sponsored by drug companies that make vaccines.
The results provide "valid scientific information that continues to show the safety of this vaccine," said Dr. Harold S. Margolis, chief of the CDC's hepatitis branch, who was not involved in the research.
The Harvard researchers looked at whether the vaccine can cause MS in healthy people. They culled MS patients from two studies of nurses and looked at their vaccination records. They compared 192 nurses who have MS to 645 nurses who did not have the illness.
They found that the vaccinated women in each group were at no more risk for developing MS than those who were not vaccinated.
The second study looked at whether vaccinations, including hepatitis B, tetanus and flu, trigger a flare-up of symptoms in MS patients. Researchers studied 643 MS patients in Europe who had suffered their first relapse in at least a year. Multiple sclerosis, which attacks the central nervous system, has no known cause and its symptoms can come and go.
The researchers concluded that vaccination does not appear to increase the risk of relapse.
"There was not even a little hint that something is going on. For me, the books are closed with respect to this issue," said Samy Suissa of McGill University in Montreal, one of the researchers.
Drs. Bruce G. Gellin and William Schaffner of Vanderbilt University School of Medicine wrote in an accompanying editorial: "The results of these studies should provide reassurance to recipients of these vaccines, to patients with multiple sclerosis, and to their patients."
On the Net:
New England Journal of Medicine: http://www.nejm.org
Centers for Disease Control: http://cdc.gov
American Liver Foundation: http://liverfoundation.org
The National Multiple
Sclerosis Society: http://www.nmss.org
© 2001 The Associated