ATLANTA, Ga-Doctors have long questioned whether a vaccine to prevent hepatitis B caused multiple sclerosis.
A new study says the two were unfairly linked-there is no trigger in the vaccine that causes other diseases, researchers reported.
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 (CDC) estimates 1.25 million Americans have chronic hepatitis B infections.
The vaccines has been available since 1982 and required for most school children since 1991. An estimated 20 million Americans have received the injections, including healthcare workers.
The first concerns came in 1998 when the French government stopped a major vaccination program because of fears that the injection caused neurological disorders, including multiple sclerosis.
An article was published in September in the New England Journal of Medicine warning doctors should give the shots only to MS patients who are at substantial risk. They feared the vaccine might trigger the disease.
But the new study proves otherwise. Looking at 192 nurses who had MS and 645 nurses who did not have the disease, Harvard researchers found the vaccinated women in each group were at no more risk for developing MS than those who were not vaccinated.
A second study focused on whether vaccinations cause flare-up symptoms in MS patients. Researchers looked at 643 MS patients in Europe who had suffered their first relapse in at least a year.
The study showed no connection to any vaccination and MS flare-ups.
Multiple sclerosis, which attacks the central nervous system, has no known cause and its symptoms come at random.