New Vaccine Candidate Shows Promise Against Lyme Disease

Pfizer and Valneva have announced promising phase 3 results for their investigational Lyme disease vaccine candidate, PF-07307405 (also known as LB6V). The findings, from the large VALOR clinical trial, mark an important step forward in the effort to prevent Lyme disease, currently the most common vector-borne illness in the Northern Hemisphere.

“Lyme disease can cause potentially serious consequences — where individuals and families face symptoms that can disrupt daily life, work and long-term health — and there is currently no vaccine available,” said Annaliesa Anderson, Ph.D., senior vice president and chief vaccines officer at Pfizer. “The efficacy shown in the VALOR study of more than 70% is highly encouraging and creates confidence in the vaccine’s potential to protect against this disease that can be debilitating.”

In the trial, the vaccine demonstrated more than 70% efficacy in preventing confirmed cases of Lyme disease in individuals aged 5 years and older. Specifically, efficacy reached 73.2% starting 28 days after the fourth dose and 74.8% just one day after the fourth dose during the second Lyme disease season. While the study did not fully meet one of its prespecified statistical thresholds — due in part to fewer-than-expected cases — researchers emphasized that the overall results remain clinically meaningful and support continued development.

Importantly, the vaccine was also well tolerated, with no major safety concerns identified at the time of analysis. This combination of efficacy and safety has strengthened confidence in the vaccine’s potential, and Pfizer has announced plans to move forward with regulatory submissions.

PF-07307405 is particularly notable because there are currently no approved vaccines for Lyme disease in humans. The vaccine uses a targeted approach, prompting the immune system to produce antibodies against six types of Borrelia bacteria (the organisms responsible for Lyme disease). These antibodies work inside the tick during feeding, blocking transmission before infection can occur.

“These results bring us a step closer to our goal of delivering a much-needed vaccine to help protect against Lyme disease,” said Thomas Lingelbach, CEO and board member of Valneva. “We are grateful to our partner Pfizer for their strong commitment, which we both share in developing this vaccine as quickly as possible.”

The need for prevention tools is growing. In the U.S. alone, hundreds of thousands of people are diagnosed and treated for Lyme disease each year. Early symptoms can be mild or mistaken for other conditions, but untreated infections can lead to serious complications affecting the joints, heart and nervous system.

If approved, this vaccine could become the first widely available option to help reduce Lyme disease risk, especially for people in high-exposure areas.