FDA panel backs Lyme disease vaccine

The LYMErix vaccine

BETHESDA, Maryland (CNN) -- Government scientists cautiously recommended Tuesday that the first vaccine against Lyme disease be approved for sale in the United States. The vaccine, called LYMErix, requires three shots over a year's time and is about 80 percent effective.

The advisory panel for the Food and Drug Administration added several warnings to its approval of LYMErix: it should not be used by children under 16 or people with chronic arthritis, and no one should receive booster shots until the drug's maker, SmithKline Beecham, completes further study.

The FDA is not bound by the panel's recommendations but typically follows them.

Because Lyme disease is a serious threat in parts of the country, "the benefits are on the side of the vaccine in the short term," said Dr. Dixie Snider of the Centers for Disease Control and Prevention. "In the long term, we don't know."

El Niño could mean more ticks

Lyme disease is spread by tiny deer ticks, and 1998 could be a banner year for the insects.

Deer tick

Dr. Philip Baker of the National Institutes of Health told CNN, "We expect there might be an increase this year and perhaps the following year because of the large amount of rainfall we've had with El Niño."

Lyme disease can be cured with antibiotics if it's recognized and treated quickly, but the symptoms are often overlooked. Left untreated, it can severely damage the heart and nervous system and cause debilitating arthritis.

Symptoms include a bull's-eye shaped rash, fatigue, chills, fever and joint pain. Cases have occurred in 49 states but are most common in the Northeast and upper Midwest.

LYMErix is unlike typical vaccines that fight infection already inside the body. LYMErix creates antibodies that recognize an outer protein of the Lyme bacterium called Osp-A.

When the tick begins sucking a vaccinated person's blood, it would also ingest these antibodies, which would neutralize the Lyme germs before they enter the tick's victim.

Keep checking for ticks

In a study of 10,936 people in high-Lyme states, LYMErix proved 79 percent effective at preventing Lyme infections after the third dose.

But the third dose is given a full year after the first shot, and the vaccine is only 50 percent effective in that first year. Once people got the third shot, their level of protective antibodies increased tenfold.

So people still must check for ticks.

"There's going to have to be a lot of patient education. That dose you got before warm weather this year ... doesn't allow you to go play in the woods willy-nilly," said Dr. Robert Daum of the University of Chicago.

LYMErix's main side effects were soreness and swelling at the vaccine site, plus a few days of joint pain, fatigue and fever. SmithKline has begun studies to answer some of the panel's questions, including booster doses and the vaccine's effect in children, but most of the results will not be available in time for next year's tick season.

Related stories:

• El Niño = big bug boost this summer - May 25, 1998
• El Niño winds could stir up wave of tropical diseases - March 12, 1998

Related sites:

• Food and Drug Administration Home Page
• SmithKline Beecham
  • SmithKline Beecham's LYMErixTM Found Safe and Effective For Prevention of Lyme Disease by FDA Advisory Committee - May 26, 1998
• Centers for Disease Control and Prevention Home Page
  • Lyme Disease
• American Lyme Disease Foundation