Major Test of First Possible Lyme Vaccine In 20 Years Begins

An anonymous reader quotes a report from The Associated Press: Researchers are seeking thousands of volunteers in the U.S. and Europe to test the first potential vaccine against Lyme disease in 20 years -- in hopes of better fighting the tick-borne threat. Lyme is a growing problem, with cases rising and warming weather helping ticks expand their habitat. While a vaccine for dogs has long been available, the only Lyme vaccine for humans was pulled off the U.S. market in 2002 from lack of demand, leaving people to rely on bug spray and tick checks. Now Pfizer and French biotech Valneva are aiming to avoid previous pitfalls in developing a new vaccine to protect both adults and kids as young as 5 from the most common Lyme strains on two continents.

Most vaccines against other diseases work after people are exposed to a germ. The Lyme vaccine offers a different strategy -- working a step earlier to block a tick bite from transmitting the infection, said Dr. Gary Wormser, a Lyme expert at New York Medical College who isn't involved with the new research. How? It targets an 'outer surface protein' of the Lyme bacterium called OspA that's present in the tick's gut. It's estimated a tick must feed on someone for about 36 hours before the bacteria spreads to its victim. That delay gives time for antibodies the tick ingests from a vaccinated person's blood to attack the germs right at the source.

In small, early-stage studies, Pfizer and Valneva reported no safety problems and a good immune response. The newest study will test if the vaccine, called VLA15, really protects and is safe. The companies aim to recruit at least 6,000 people in Lyme-prone areas including the Northeast U.S. plus Finland, Germany, the Netherlands, Poland and Sweden. They'll receive three shots, either the vaccine or a placebo, between now and next spring's tick season. A year later, they'll get a single booster dose.

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