Scientists have found that people who develop multiple sclerosis (MS) are more likely than others to have received a hepatitis B vaccination in recent years. Earlier studies investigating a link between the muscle-weakening disease and the vaccine had produced predominantly negative results.
"We were very surprised" by the new finding, says study coauthor Miguel A. Hernán, an epidemiologist at the Harvard School of Public Health in Boston.
Hernán and his colleagues identified 163 MS patients in Britain who had been diagnosed with MS between 1993 and 2000. The scientists matched these patients with 1,604 people without MS who had used the same physicians' offices and were of similar age, gender, and smoking status.