Pfizer and Valneva Announce Positive Phase 3 Results for Lyme Disease Vaccine Candidate

Pfizer and Valneva announced positive topline results from the phase 3 VALOR (NCT05477524) clinical trial for their investigational Lyme disease vaccine candidate, PF-07307405. The study, also known as Vaccine Against Lyme for Outdoor Recreationists, demonstrated an efficacy of 73.2% in preventing confirmed Lyme disease cases when measured 28 days after the fourth dose. These results represent a critical milestone, as there are currently no approved human vaccines available to combat the growing threat of Lyme disease in the Northern Hemisphere.¹

“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,” Annaliesa Anderson, PhD, senior vice president and chief vaccines officer at Pfizer, said in a news release.¹ “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.”

The vaccine candidate, a 6-valent outer surface protein A (OspA)-based protein subunit vaccine, utilizes a unique mechanism of action designed to intercept transmission at the source. Upon vaccination, an individual develops antibodies against 6 prevalent serotypes of the Borrelia burgdorferi bacteria. When an infected tick feeds on the vaccinated person, it ingests these antibodies, which then bind to the OspA within the tick’s midgut. This binding action prevents the bacteria from migrating to the tick's salivary glands, thereby blocking transmission to the human host.^1,2

The VALOR trial enrolled participants 5 years and older across high-incidence areas in the United States, Canada, and Europe. The dosing regimen tested in the study involved a primary series at months zero, 2, and 5 to 9, followed by a fourth dose administered 1 year later, strategically timed just before the start of the next Lyme disease season.¹

Although the primary end point's statistical criterion for the 95% confidence interval was not met in the first prespecified analysis due to fewer than anticipated cases, the clinical efficacy remains over 70%, and the second prespecified analysis met the necessary statistical benchmarks.¹

For pharmacists and health care providers, the vaccine represents a potential solution to a worsening epidemiological trend. The Centers for Disease Control and Prevention (CDC) estimates that approximately 476,000 people are diagnosed and treated for Lyme disease annually in the United States, with another 132,000 cases reported in Europe. The geographic footprint of the disease continues to widen, increasing the medical necessity for preventative measures. Currently, the clinical management of Lyme disease relies heavily on early detection of symptoms such as the erythema migrans "bullseye" rash, fever, and fatigue. If left untreated, the infection can lead to severe systemic complications including arthritis, Lyme carditis, and neurological impairment.^1-3

Earlier phase 2 data further support the clinical profile of the vaccine, particularly regarding immunogenicity and the necessity of the multidose schedule. Final phase 2 results indicated that antibody levels remained significantly above baseline across all age groups 6 months after a third annual booster. The study also validated the 3-dose primary vaccination series, which produced higher antibody levels than a 2-dose alternative. Pharmacists will likely play a key role in managing this multidose schedule and educating patients on the importance of boosters to maintain protection.²

“These results bring us a step closer to our goal of delivering a much-needed vaccine to help protect against Lyme disease. We are grateful to our partner Pfizer for their strong commitment which we both share in developing this vaccine as quickly as possible,” Thomas Lingelbach, CEO and board member of Valneva, said in a news release.¹

With the completion of the pivotal phase 3 trials, Pfizer is now planning to submit a biologics license application to the US Food and Drug Administration and a marketing authorization application to the European Medicines Agency in 2026. The potential introduction of PF-07307405 would provide the first vaccine-based defense against a systemic infection that can cause debilitating long-term health disruptions.^1,2

READ MORE: Immunizations Resource Center

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REFERENCES

1. Pfizer and Valneva announce Lyme disease vaccine candidate demonstrates strong efficacy in phase 3 VALOR trial. News release. Pfizer. March 23, 2026. Accessed March 23, 2026. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-valneva-announce-lyme-disease-vaccine-candidate

2. Valneva announces positive final phase 2 results for Lyme disease vaccine candidate. News release. Valneva. News release. November 26, 2025. Accessed March 23, 2026. https://valneva.com/wp-content/uploads/2025/11/2025_11_26_VLA15_221_Phase-2_Results-1.pdf

3. CDC. Signs and symptoms of untreated Lyme disease. May 14, 2024. Accessed March 23, 2026. https://www.cdc.gov/lyme/signs-symptoms/?CDC_AAref_Val=https://www.cdc.gov/lyme/signs_symptoms/index.html