NEW YORK (Reuters Health) ¿ Vaccinating against hepatitis B virus (HBV) does not increase a child's risk of developing multiple sclerosis (MS), according to a study released this week.

Most prior studies have not shown a link between the use of HBV vaccine and MS in children, Dr. Yann Mikaeloff, from Hopital Bicetre, Le Kremlin Bicetre, and colleagues note in the Archives of Pediatrics and Adolescent Medicine. However, one study, which featured a slightly longer follow-up period than the others, did suggest a significant association. This led to public concerns about the safety of the HBV vaccine and a drop in vaccination rates in many countries.

Furthermore, many of the earlier studies had "methodologic" problems, the investigators say, which may have prevented them from reaching definitive conclusions.

Against this backdrop, Mikaeloff and colleagues assessed 143 children who developed MS before age 16, with a first episode of the disease occurring between 1994 and 2003. Each patient was matched to an average of eight control participants from the general French population who were the same age and sex and lived in the same location but did not have MS.

In the three years before the first episode of MS, roughly 32 percent of both the 143 children with MS and the 1,122 controls were vaccinated against hepatitis B.

Mikaeloff and colleagues report that vaccination against hepatitis B within the three-year study period was not associated with an increased rate of a first episode of MS.

"The rate was also not increased for hepatitis B vaccination within six months of the index date or at any time since birth or as a function of the number of injections or the brand of hepatitis B vaccine."

In a related editorial, Dr. Frederick P. Rivara and Dr. Dimitri A. Christakis, at the University of Washington and editors of the Archives of Pediatrics and Adolescent Medicine, write: "We have published (this study) both because of the rigor of the research and because of the need to reassure a public that is increasingly wary of vaccination."

"Going forward, we hope that the process of scientific discovery proceeds in a rigorous and thoughtful way that will increase the public's health and not harm it."