Pfizer and its French biotech company partner Valneva SE are launching the large phase 3 clinical trial of an experimental vaccine that will prevent Lyme disease as more than 14% of the global population shows signs of infection.

If proven safe and effective, the vaccine called VLA15 could be useful in stopping the tick-borne disease that has affected almost half a million Americans each year. Some may clear their symptoms using antibiotics, but others continue to suffer from lingering symptoms for many years.

Phase 3 Clinical Trial for VLA15 Vaccine

Pfizer has been collaborating with Valneva SE to co-develop a Lyme disease vaccine since April 2020. The earlier trials were conducted in both labs, USA Today reported.

The vaccine "demonstrated a strong immune response and satisfactory safety profile," according to the company.

In this trial in which the American drugmaker agreed to make a $25 million milestone payment to Valneva, the companies will enroll 6,000 participants from ages 5 and older in as many as 50 sites across Lyme disease-endemic regions in Europe and the US.

The VLA15 vaccine is delivered in three primary doses and followed by one booster shot. Participants will be divided into two groups in which one group receives the vaccine and the other a saline placebo.

The vaccine targets the outer surface of the Borrelia burgdorferi, the bacterium that causes Lyme disease, to inhibit its ability to jump from tick to person. It protects against six forms of the protein expressed by the bacteria found in North America and Europe.

If all goes well during this phase 3 clinical trial, Pfizer and Valneva will request approval from the Food and Drug Administration (FDA) by 2025. 

Pfizer senior vice president Annaliesa Anderson emphasized the importance of providing new options to help people protect themselves from Lyme disease.

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(Photo : BERTRAND GUAY/AFP via Getty Images)
A picture taken at the French National Institute of Agricultural Research (INRA) in Maison-Alfort, on July 20, 2016 shows a tick, whose bite can transmit the Lyme disease.

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What We Know About VLA15 Vaccine

According to a news release from Valneva, VLA15 is the only existing Lyme disease vaccine in clinical development today. The vaccine uses an established mechanism of action against the tick-borne disease and targets the outer surface protein A (OspA) of the bacteria that causes Lyme disease.

Borrelia burgdorferi expresses OspA when it is present in a tick. The vaccine aims to block OspA and prevent the bacteria from leaving the tick and infecting people. One of the six forms of the bacteria the vaccine can stop is the Borrelia burgdorferi sensu lato species, which is most commonly seen in North America and Europe. So far, the trials of VLA15 show promising results.

Lyme disease is a systemic infection transmitted to humans by infected ticks and is considered the most common tick-borne illness in the Northern Hemisphere. It is estimated that around 476,000 people are infected in the US and 130,000 in Europe.

Early signs of the infection could include rash, fatigue, fever, headache, mild stiff neck, and myalgia. But they are often misinterpreted and left untreated they cause more severe complications that affect the joints, heart, and nervous system. The increasing number of cases creates a medical need for vaccination to prevent further transmission.

RELATED ARTICLE: Lyme Disease Causing Ticks at Highest Density in White Woods Pennsylvania [Report]

Check out more news and information on Lyme Disease in Science Times.