Lyme disease: Final trial ends 20-year wait for tick-borne disease vaccine

Researchers are looking for thousands of volunteers in the United States and Europe to test the first potential Lyme disease vaccine in 20 years in hopes of better combating the tick-borne threat.

Lyme is a growing problem, with cases rising and global warming helping ticks expand their habitat.

While a vaccine for dogs has long been available, the only Lyme disease vaccine for humans was pulled from the US market in 2002 due to lack of demand, leaving people to rely on insect repellents and controls ticks.

Today, Pfizer and French biotech Valneva aim to avoid previous pitfalls in developing a new vaccine to protect adults and children as young as 5 years old against the most common strains of Lyme on two continents.

“There was no such recognition, I think, of the seriousness of Lyme disease” and the number of people it affects last time around, Pfizer’s head of vaccines told The Associated Press, Annaliesa Anderson.

Robert Terwilliger, an avid hunter and hiker, was on the front lines Friday when the study opened in central Pennsylvania. He has seen many friends contract Lyme disease and is tired of wondering if his next tick bite will make him sick.

“It’s always a worry, you know? Especially when you’re sitting in a tree hunting and you feel something crawling on you,” said Terwilliger, 60, of Williamsburg, Pennsylvania. “You have to be very, very careful.”

What are the symptoms of Lyme disease?

The exact frequency of Lyme disease is unclear. The Centers for Disease Control and Prevention (CDC) cites insurance records suggesting that 476,000 people are treated for Lyme in the United States each year. Pfizer’s Anderson put annual infections in Europe at around 130,000.

Blacklegged ticks, also called deer ticks, carry bacteria that cause Lyme disease. The infection initially causes fatigue, fever and joint pain. Often – but not always – the first sign is a red, round, bulls-eye rash.

Early antibiotic treatment is crucial, but it can be difficult for people to tell if they’ve been bitten by ticks, some as small as a pin. Untreated Lyme disease can cause severe arthritis and damage to the heart and nervous system. Some people have persistent symptoms even after treatment.

Most vaccines against other diseases work after people have been exposed to a germ. The Lyme vaccine offers a different strategy – working a little earlier to prevent a tick bite from transmitting the infection, said Dr. Gary Wormser, a Lyme expert at New York Medical College who is not involved in the news. research.

How does the Lyme vaccine work?

It targets an “outer surface protein” of Lyme bacteria called OspA that is present in the tick’s gut. It is estimated that a tick must 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 latest study will test whether the vaccine, called VLA15, really protects and is safe.

The companies aim to recruit at least 6,000 people from Lyme risk regions, including the northeastern United States, Finland, Germany, the Netherlands, Poland and Sweden.

They will receive three injections, either the vaccine or a placebo, by next spring tick season. A year later, they will receive a single booster dose.

“We’re really looking at 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 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 leads the one of the Altoona Center study sites. for clinical research in Duncansville, Pennsylvania.

In her own practice, “not a day goes by that someone isn’t concerned about Lyme disease, or at risk of having Lyme disease,” Kivitz said.

How is this vaccine different from older Lyme disease vaccines?

This new candidate is different from an earlier Lyme vaccine that GlaxoSmithKline pulled from the market in 2002 amid controversy and poor sales.

With around 75% efficacy, this old Lyme vaccine has received lukewarm approval from vaccine experts, hasn’t been tested in children, and has prompted unsubstantiated reports of joint-related side effects. .

While the new Pfizer-Valneva vaccine also targets the OspA protein, it is designed somewhat differently from its predecessor and also targets six Lyme strains in the United States and Europe instead of just one.

Pfizer’s study will span two tick seasons to get some answers — but it’s not the only research into new ways to prevent Lyme. Scientists at the University of Massachusetts are working on an alternative to the vaccine, injections of pre-made Lyme antibodies.

And researchers at Yale University are in the early stages of designing a vaccine that recognizes the saliva of a tick – which, in animal tests, triggered a skin reaction that made it harder for ticks from latching onto and feeding.

Since different species of ticks carry many non-Lyme diseases, ultimately “we’re all hoping for a vaccine against tick bites,” Wormser said.