Lyme Vaccine for Humans: The Race for a New Vaccine

Lyme vaccine for humans remains an important goal, but past challenges continue to shape the path forward. LYMErix was withdrawn from the market in 2002 after concerns over its safety, raising ongoing questions about whether researchers can develop an effective and safe Lyme disease vaccine.

The stakes are high in the race for a new Lyme vaccine for humans. “There will be one more shot at bringing a human Lyme vaccine to market, and if that vaccine fails, the market will essentially disappear,” states Richard Marconi, an immunologist working on a vaccine based on a dog vaccine released in 2006.¹

At the forefront is the European company Valneva, which has been developing a vaccine targeting multiple strains of Borrelia, writes Shaffer.¹ The company has received fast-track status from the U.S. Food and Drug Administration (FDA).

Valneva’s approach avoids the epitope that was associated with autoimmune reactions alleged to occur with LYMErix. Meanwhile, Marconi’s vaccine targets a different OspC protein, with the goal of improving acceptance based on its track record in pets. However, developing an OspC vaccine has been challenging due to variability between strains.

I had a medical practice in Westchester, NY, when the LYMErix vaccine was first introduced. That spring, more than 300 doctors and researchers were asked at an international Lyme disease conference how many would personally take the vaccine. Only 3 people raised their hands. The moderator questioned whether LYMErix would succeed if leading experts were reluctant to use it.

I discussed with my patients the pros and cons of LYMErix, which was about 80% effective at preventing an erythema migrans rash. The vaccine was only 50% effective at preventing “possible Lyme,” according to the package insert.

“Possible Lyme” was defined as a flu-like illness (fever, chills, fatigue, headache, joint or muscle aches) with IgM or IgG Western blot seroconversion, or physician-diagnosed erythema migrans with negative laboratory results. These symptoms often overlap with early Lyme disease symptoms.

There was no available data on the effectiveness or safety of the vaccine for children under age 15. In addition, individuals needed three doses of LYMErix over two tick seasons, and periodic boosters were expected to be necessary.

The biggest roadblock stemmed from concerns that the vaccine caused an autoimmune reaction in some recipients.

If a new Lyme vaccine for humans becomes available, individuals may remain hesitant until there is full transparency regarding what led to the withdrawal of LYMErix. As Pat Smith, president of the Lyme Disease Association, emphasized, any new vaccine manufacturer will need to clarify what went wrong.

Note: None of the new vaccines described address protection against co-infections such as Babesia.

Although much attention has focused on vaccines, alternative strategies are being explored. “The ideal strategy,” writes Shaffer, “would target the tick itself,” by interfering with proteins in the tick’s saliva or mid-gut to prevent transmission of Lyme disease and other pathogens. This aligns with ongoing efforts in Lyme disease prevention.

I had patients who were reluctant to take the LYMErix vaccine. I rarely prescribed it and did not observe autoimmune reactions in my practice. Many patients today express similar concerns about any future Lyme vaccine for humans.

Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

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