DUNCANSVILLE, Pa. (AP) – Researchers are seeking thousands of volunteers in the U.S. and Europe to test the first potential Lyme disease vaccine in 20 years, hoping to better fight the tick threat.
Lyme is a growing problem, with increasing cases and warming weather helping ticks expand their habitat. Although a dog vaccine has long been available, the only Lyme vaccine for humans was pulled from the US market in 2002 due to lack of demand, leading people to rely on bug spray and tick controls.
Now Pfizer and French biotech Valneva aim to avoid earlier pitfalls in developing a new vaccine to protect both adults and children up to 5 years old from the most common strains of Lyme on both continents.
“I think there was not as much recognition of how serious Lyme disease is” and how many people it affects last time, Annaliesa Anderson, Pfizer’s vaccine chief, told The Associated Press.
Robert Terwilliger, an avid hunter and hiker, was the first Friday when the studio opened in central Pennsylvania. He’s seen many friends get Lyme and is tired of wondering if his next tick bite will make him sick.
“It’s always a concern, you know? Especially when you’re sitting in a tree hunting and you feel something creep up on you,” said Terwilliger, 60, of Williamsburg, Pennsylvania. “You have to be very, very careful.”
It’s not clear how often Lyme disease affects you. The Centers for Disease Control and Prevention cites insurance records that suggest 476,000 people are treated for Lyme in the US each year. Pfizer’s Anderson put Europe’s annual infections at about 130,000.
Black-legged ticks, also called deer ticks, carry bacteria that cause Lyme. The infection initially causes fatigue, fever and joint pain. Often, but not always, the first sign is a red, round rash.
Early antibiotic treatment is crucial, but it can be difficult for people to know if they have been bitten by ticks, some as small as a pin. Untreated Lyme can cause severe arthritis and damage the heart and nervous system. Some people have persistent symptoms even after treatment.
Most vaccines against other diseases work after people are exposed to a germ. The Lyme vaccine offers a different strategy: working one step earlier to prevent a tick bite from transmitting the infection, said Dr. Gary Wormser, a Lyme expert at New York Medical College who was not involved in the new research.
How? It targets an “outer surface protein” of the Lyme bacteria called OspA that is present in the tick’s gut. It is estimated that a tick has to feed on someone for about 36 hours before the bacteria spreads to its victim. This delay gives time for the antibodies that the tick ingests from the blood of a vaccinated person to attack the germs directly at the source.
In small, early-stage studies, Pfizer and Valneva reported no safety issues and a good immune response. The newest study will test whether 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 northeastern United States plus Finland, Germany, the Netherlands, Poland and Sweden.
They will receive three injections, either the vaccine or a placebo, between now and next spring’s tick season. A year later, they will receive a single booster dose.
“We’re really looking for something that’s a seasonal vaccine,” Anderson said, so people have high antibody levels during the months when ticks are most active.
Volunteers can be as young as 5 years old and should be at high risk because they spend a lot of time in tick-infested areas, such as hikers, campers and hunters, said Dr. Alan Kivitz, who runs one of the sites of study from the Altoona Center for Clinical Research in Duncansville, Pennsylvania.
In his own practice, “not a single day goes by that someone has a concern about Lyme disease, could possibly have Lyme disease,” Kivitz said.
This new candidate is different from an earlier Lyme vaccine that GlaxoSmithKline pulled from the market in 2002 amid controversy and poor sales. About 75% effective, that old Lyme shot got lukewarm support from vaccine experts, wasn’t tested in children, and drew unsubstantiated reports of joint-related side effects.
While the new Pfizer-Valneva vaccine also targets the OspA protein, it has been designed slightly differently than its predecessor and also targets six strains of Lyme in the US and Europe instead of one alone
The Pfizer study will span two seasons to get answers, but it’s not the only research into new ways to prevent Lyme. Scientists at the University of Massachusetts are working on a vaccine alternative, made from pre-made Lyme-fighting antibodies.
And researchers at Yale University are in the early stages of designing a vaccine that recognizes a tick’s saliva, which in animal tests caused a skin reaction that made it harder for ticks to hold on and feed themselves
Because different species of ticks carry many different Lyme diseases, ultimately, “we’re all hoping for a vaccine for tick bite prevention,” Wormser said.
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The Associated Press Department of Health and Science is supported by the Department of Science Education at the Howard Hughes Medical Institute. The AP is solely responsible for all content.