Hepatitis B vaccine: a study shows a tripling of the risk of multiple sclerosis

The U.S. study showing a tripling of the risk of multiple sclerosis (MS) associated with the recombinant vaccine against hepatitis B in the United Kingdom whose preliminary results are already known vaccine is published in the journal "Neurology

The consensus meeting was held in France on vaccination against hepatitis B had spent considerable time on the results of this study, presented by the principal author, Miguel Hernan, Harvard School of Public Health in Boston.

Several studies have evaluated the potential association between vaccination against hepatitis B and the risk of developing MS or demyelinating disease, recall Miguel Hernan and colleagues in the journal Neurology.

Most have shown no increased risk, but "some of them have methodological limitations, including on retrospective verification of vaccination status on the use of date of diagnosis or inaccurate dates of first symptoms September and a small sample size, "say the researchers.

They feel they have tried to avoid this bias by conducting a case-control study nested in a cohort from a data base of British GPs on more than 3 million patients.

The analysis included 163 MS patients, whose diagnosis was made between January 1993 and December 2000 and 1604 controls.

It showed that 6.7% of patients had received at least a recombinant vaccine against hepatitis B in the three years preceding the date of the first symptoms, against only 2.4% of the control vaccine.

The risk of developing MS was then multiplied by 3.1 in the case of vaccination against hepatitis B in the three years before the first symptoms, compared to an absence of HBV vaccination.

However, no increased risk of developing MS was observed with vaccination against influenza and against tetanus.

"These results are consistent with the hypothesis that immunization with recombinant vaccine against hepatitis B is associated with an increased risk of Sept. They challenge the idea that the relationship between vaccination against hepatitis B and the risk of MS is well understood, "the authors conclude.

However, they highlight the fact that 93% of MS patients in their study were not vaccinated against hepatitis B and that "any decision regarding vaccination against hepatitis B should take into account the important benefits from preventing a common and potentially deadly "infection.

Finally, "our study does not distinguish whether the vaccine against hepatitis B accelerates the development of MS in people predestined to develop the disease in the years to come, or if it causes new cases of MS in patients sensitive, "the researchers added.

However, the first explanation seems unlikely because of the similar age of first symptoms between vaccinated and unvaccinated cases, they say.

In an accompanying editorial, Robert Naismith and Anne Cross of Washington University in St. Louis noted that this study should be considered as "another piece to the puzzle that are the causes of MS, but [that] the data presented do not provide evidence of sufficient Association to implement changes in vaccination policies. "

The authors also question the selection of patients who may have introduced bias unrecognized while the goal was initially to avoid bias alleged against other studies