Lyme disease is a tick-borne illness caused by the bacterium Borrelia burgdorferi. If not addressed, it can lead to long-term health complications, making vaccine development a public health objective. The journey toward a reliable vaccine has been complex, marked by advancements and setbacks. This history provides context for current efforts to protect populations from this disease.
The Original Human Lyme Vaccine
The first and only Lyme disease vaccine approved for human use by the U.S. Food and Drug Administration (FDA) was LYMErix, manufactured by GlaxoSmithKline. Introduced in 1998, the vaccine targeted the Outer surface protein A (OspA) of the Borrelia burgdorferi bacterium. It worked by stimulating antibodies in the human host, which would then be ingested by a feeding tick and neutralize the bacteria within the tick’s gut, preventing transmission.
Clinical trials demonstrated that LYMErix was approximately 78% effective in preventing infection after a three-dose series. Despite this promising start, the vaccine’s time on the market was short-lived. Soon after its release, reports began to surface linking the vaccine to adverse events, most notably arthritis. These concerns were amplified by media coverage and led to a class-action lawsuit against the manufacturer.
In response, both the FDA and the Centers for Disease Control and Prevention (CDC) conducted reviews. Their expert panels found insufficient evidence to establish a causal link between the vaccine and the reported cases of arthritis. However, the damage to public perception was done. The combination of negative press, litigation, and vaccine skepticism contributed to a sharp decline in sales. Citing poor market performance, GlaxoSmithKline voluntarily withdrew LYMErix from the market in 2002.
The Next Generation of Lyme Vaccines
With LYMErix off the market, the search for a new Lyme disease vaccine has become a priority as infection rates rise. Several candidates are in development, but the most prominent is VLA15, a collaboration between Pfizer and Valneva. This vaccine candidate is in Phase 3 clinical trials, the final stage before a potential submission for regulatory approval. The trial is being conducted in areas where Lyme disease is highly prevalent, including the United States and Europe.
VLA15 builds upon the science of its predecessor but incorporates improvements. Like LYMErix, it targets the OspA protein of the Lyme-causing bacteria. A significant advancement is that VLA15 is a multivalent vaccine, designed to protect against multiple serotypes of the Borrelia bacterium. This broader approach aims to provide protection against the most common strains in both North America and Europe.
The development of VLA15 is being closely watched, as its approval would mark the first time in over two decades that a vaccine for Lyme disease is available. The clinical trial is expected to conclude near the end of 2025, with a potential submission to the FDA for approval anticipated in 2026. Beyond VLA15, researchers are also exploring other innovative approaches, including the use of mRNA technology. These next-generation strategies signal a renewed effort to provide a tool in the fight against Lyme disease.
Preventing Lyme Disease Now
While the development of a new vaccine progresses, individuals are not defenseless against Lyme disease. Several non-vaccine prevention strategies can reduce the risk of tick bites and subsequent infection. These methods focus on personal protection and creating safer environments in areas where ticks are common.
Effective prevention methods include:
- Conducting thorough tick checks after spending time outdoors, particularly in wooded or grassy areas, and inspecting the entire body.
- Using an EPA-registered insect repellent containing active ingredients such as DEET or picaridin on exposed skin and clothing.
- Wearing protective clothing, such as long-sleeved shirts and long pants tucked into socks, to create a barrier against ticks.
- Modifying the area around one’s home by keeping grass mowed, removing leaf litter, and creating a border between lawns and wooded areas.