First Vaccine to Halt Lyme Disease OKd
The Food and Drug Administration on Monday approved the first vaccine to prevent debilitating Lyme disease, the nation’s most common tick-borne ailment and an increasingly serious problem in California, the Midwest and the Northeast.
The disease’s symptoms--which resemble the flu and often begin with a characteristic bull’s eye type of rash--often are ignored or misdiagnosed, leading to crippling nervous system and joint problems and heart abnormalities that can surface months, even years, after the initial tick bite.
The three primary areas where the disease is endemic are the West Coast, specifically Northern California and the Oregon coast; Wisconsin and Minnesota in the Midwest; and along the Northeast coast, from Massachusetts to Maryland.
Earlier this year, health officials in Los Angeles County issued a warning to individuals who frequent the Santa Monica Mountains, after confirming evidence of the disease in a tick found by a hiker at Topanga State Park. It was the first time a tick found in Los Angeles County had tested positive for carrying the disease, officials said.
Although the Lyme disease situation is far more severe in the Northeast than in the West, the problem has been growing in California. In 1997, there were 172 reported cases in the state, representing a 100% increase from the previous year, according to the federal Centers for Disease Control and Prevention.
Since 1982, more than 100,000 cases of the disease have been reported from 48 states, although most experts believe this is a gross underestimate of the total.
Lyme disease, which takes its name from the Connecticut town where it was first identified in 1975, is caused by the spiral-shaped bacterium Borrelia burgdorferi that is carried by deer ticks.
The vaccine LYMErix, made by Philadelphia-based SmithKline Beecham Biologicals, requires three injections over a year to build immunity and is recommended for individuals older than 15 who live or work in grassy or wooded areas where infected ticks are present.
The second injection is given one month after the first, and the third is administered 12 months after the first.
“We’re very excited. The vaccine is really going to help--there’s no question in my mind,” said David Weld, executive director of the American Lyme Disease Foundation. He believes there have been up to tenfold more cases than those thus far documented.
The vaccine, created by UC Irvine professor Alan Barbour, will be available within two weeks, an optimal time to begin injections to help protect against next summer’s tick crop. The company would not divulge its cost. However, since it is a licensed vaccine, it is likely to be covered by most health insurance programs.
The vaccine is not yet approved for use in children because, until recently, it had not been studied in children. Such studies are underway although not yet complete, the company said.
After two doses of the vaccine in the first year of trials, the protection rate was 50%, and in the second year, after three doses, it was 78%. It is not known how long protection will last after vaccination. It is possible that booster shots may be required.
“For people who spend a lot of time outdoors in areas where Lyme disease is common, this new vaccine may be a good option,” said FDA Commissioner Jane E. Henney. “However, this vaccine’s effectiveness depends on people getting all three doses over the period of a year. We also want to emphasize that the vaccine is not 100% effective, so other precautions should be taken.”
The vaccine appears to protect against the most common strain of Lyme disease found in the United States but does not protect against all strains.
Therefore, the FDA urged individuals--including those who become vaccinated--to continue preventive measures when in grassy or wooded areas, including wearing light-colored clothing, long pants tucked into socks or boots and long-sleeved shirts, and using tick repellent.
“I think this is a big advance, and it should have a real impact, since this is the largest cause of insect-borne infections,” said Dr. John La Montagne, an infectious diseases expert who is deputy director of the National Institute of Allergy and Infectious Diseases.
He pointed out that preventing the disease also “will minimize the use of antibiotics,” which are used to treat the disorder, but which contribute to the growing public health problem of antibiotic-resistant bacteria. “So it is also very important in that regard,” La Montagne said.
There is variation in concentration of ticks carrying the infection among regions and states, and even among counties within a state, according to the American Lyme Disease Foundation. For example, the tick infection rate in Pacific coastal states is between 2% and 4%, while fewer than 5% of adult ticks south of Maryland are infected, the foundation said. In certain areas of the Northeast, up to 50% are infected, according to the group.
The time of the year when people get vaccinated may be significant, the agency said. During the trials, which were conducted over two years in the Northeast, most injections were given between January and April, shortly before the peak tick season in that part of the country.
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Tick and Lyme Disease Facts
Ticks can transmit Lyme disease, which is an infection caused by a bacterium called Borrelia burgdorferi. Lyme disease is prevalent in the Northeast and increasingly in wooded and/or mountainous regions of the Midwest and West Coast. The FDA approved a vaccine on Monday.
How Disease is Transmitted
An infected deer tick or related Western black-legged tick clinging to grass or foilage attaches to animals or humans as they brush against vegetation. The tick--which can measure 1/4 inch or smaller--remains attached by embedding its sharp mouth parts into victim. Symptoms usually begin one to two weeks after tick bite and include bull’s-eye-shaped rash, flu-like discomfort, joint pain, fatigue, headache, lack of concentration and facial paralysis.
Source: American Lyme Disease Foundation Inc., staff reports
