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Lyme disease-carrying ticks are on the march, spreading to more forests and bush areas in the United States and Europe. But outdoor enthusiasts could get a new weapon against Lyme, if a new candidate vaccine performs well. It aims to protect people from the age of five.
If it were to win approval from regulators, it would become the only Lyme disease vaccine available to humans in the United States. But it is expected to take years for the potential vaccine to reach the market. If the phase three study is successful, the companies say, they would likely apply for formal clearance in 2025.
The new vaccine is called VLA15, and as of this week it is now in the third phase of a clinical study in humans. It was created by Pfizer and French drugmaker Valneva.
“We are extremely pleased to have achieved this important milestone in the development of VLA15,” Valneva Chief Medical Officer Juan Carlos Jaramillo said in a statement. “Lyme disease continues to spread, representing a high unmet medical need that impacts the lives of many people in the northern hemisphere.”
American consumers once had access to a human Lyme disease vaccine, called LYMERix, but it was taken off the market 20 years ago. The vaccine had a fairly high efficacy, but some users criticized it for side effects, including arthritis. As the National Institute of Allergy and Infectious Diseases notes, “analysis by the FDA and others did not support this conclusion” — but use of the vaccine plummeted, leading to its discontinuation. There is, however, a vaccine on the US market for dogs.
The new human vaccine candidate works in a similar way to LYMERix, targeting an outer surface protein of the Borrelia bacteria responsible for Lyme disease. But VLA15 omits a protein region “that some had attributed to adverse events,” according to the NIAID.
The study that is currently underway includes some 6,000 participants in the United States and Europe who are at least 5 years old and live in places where Lyme disease is “highly endemic”, according to Pfizer and Valneva.
The vaccine candidate has elicited a strong immune response in adults and children in previous trials, “with acceptable safety and tolerability profiles,” according to the pharmaceutical companies.
Besides the potential vaccine, another weapon against Lyme is also in the works: a monoclonal antibody developed by MassBiologics, part of the University of Massachusetts Medical School. The first phase of human trials for the antibody is expected to wrap up this month, with a second phase likely starting next spring.
Lyme disease is transmitted by blacklegged ticks. Climate change and deforestation are among the human-caused factors that have increased the range of arachnids. The elimination of predators that control populations of deer and mice, two animals that carry Lyme, have also contributed to the spread of the disease.
People are at greater risk of contracting Lyme disease if a tick remains on their skin for an extended period of time, leading experts to urge people to check themselves for ticks after spending time on them. outside, especially in areas where Lyme is known to be a threat.
According to the CDC, early symptoms of Lyme can include fever, headache, and a circular rash that can look like a bulls-eye. Later symptoms may include joint pain, facial paralysis, and inflammation of the brain and spinal cord. The disease can be treated with antibiotics, especially in its early stages. Some people have been known to develop persistent symptoms, such as pain, fatigue, and an inability to concentrate.