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New Lyme Disease Vaccines Neutralize Bacteria Inside Ticks Before Infection

A late-stage clinical trial for the prophylactic Lyme disease vaccine VLA15 narrowly missed its primary efficacy target, despite demonstrating meaningful protection against the tick-borne illness. The mixed results leave the immediate regulatory future of the much-anticipated immunization uncertain.

Factlen Newsroom· Updated

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Illustration: Pfizer and Valneva's VLA15 vaccine candidate missed its primary efficacy endpoint in Phase 3 trials.From: Pfizer and Valneva Lyme Disease Vaccine Candidate Misses Primary Efficacy Endpoint in Phase 3 Trial

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Key numbers

>70%
Efficacy of Pfizer's VLA15 vaccine
6
Borrelia strains targeted by VLA15
24 years
Time since LYMErix was pulled
350
Participants in Moderna's Phase 2 trial

From: New Lyme Disease Vaccines Neutralize Bacteria Inside Ticks Before Infection

Charts, maps and images

Lyme disease cases have steadily increased, highlighting the urgent need for a prophylactic vaccine.From: Pfizer and Valneva Lyme Disease Vaccine Candidate Misses Primary Efficacy Endpoint in Phase 3 Trial ·
The vaccine targets the outer surface protein A (OspA) of the bacteria responsible for Lyme disease.From: Pfizer and Valneva Lyme Disease Vaccine Candidate Misses Primary Efficacy Endpoint in Phase 3 Trial ·
The OspA vaccine mechanism neutralizes the Lyme bacteria inside the tick's gut before it can enter the human bloodstream.From: New Lyme Disease Vaccines Neutralize Bacteria Inside Ticks Before Infection ·
Pfizer and Valneva's hexavalent vaccine demonstrated over 70% efficacy in Phase 3 trials.From: New Lyme Disease Vaccines Neutralize Bacteria Inside Ticks Before Infection ·
Illustration: The VLA15 vaccine is designed to neutralize Borrelia burgdorferi bacteria inside the tick before transmission.From: Pfizer and Valneva Lyme Disease Vaccine Candidate Misses Primary Efficacy Endpoint in Phase 3 Trial ·
Illustration: Without a vaccine, patients in endemic areas must continue to rely on early detection and antibiotic treatments.From: Pfizer and Valneva Lyme Disease Vaccine Candidate Misses Primary Efficacy Endpoint in Phase 3 Trial ·
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Expanding tick habitats have dramatically increased the risk of Lyme disease for outdoor recreationists.From: New Lyme Disease Vaccines Neutralize Bacteria Inside Ticks Before Infection ·

Timeline

October 2026

  1. Pfizer and Valneva Lyme Disease Vaccine Candidate Misses Primary Efficacy Endpoint in Phase 3 Trial

June 2026

  1. New Lyme Disease Vaccines Neutralize Bacteria Inside Ticks Before Infection