Lyme Disease Vaccine Passes Test

Scientists have made the first vaccine that appears to prevent Lyme disease. At least one of the two vaccine versions, described in tomorrow's New England Journal of Medicine, could be available by prescription as early as next spring.

Transmitted by infected ticks, the bacterium, Borrelia burgdorferi, can lead to rashes, flulike symptoms, and in rare cases, arthritis and other chronic neurological problems. Earlier animal studies revealed that one protein on the bug's outer membrane, lipoprotein A (OspA), triggers the body to produce antibodies that attack the bacterium and prevent infection. Working independently, the two teams each designed a vaccine containing OspA and tested it on more than 10,000 adults from areas where Lyme disease is relatively common, such as the northeastern and midwestern United States.

Each subject was injected with either the vaccine or a placebo, then injected again 1 month later and 1 year later. Two vaccine injections halved the risk of infection as compared to a placebo, while a third decreased the risk of infection by 75%. Subjects reported only minor side effects from the vaccine, such as inflammation at the injection site and fever. "I think it's a real advance," says Allen Steere, director of rheumatology at Boston's New England Medical Center and a study team member.

Other experts are cautiously optimistic. "We welcome new tools to prevent Lyme disease," says David Dennis, who coordinates the Lyme disease program at the Centers for Disease Control and Prevention. But he adds that the vaccine has not yet been tested on children and is not 100% effective. And because Lyme disease is mostly confined to only 10 states and can often be quickly eradicated with antibiotics, Dennis says it may be most cost-effective to target "people who are truly high risk"--such as individuals with compromised immune systems or those living in particularly tick-infested counties.