Lyme disease is the fastest-grown vector-borne illness in the United States with over 476,000 new cases annually. Cases of Lyme and other tick-borne disease are on the rise in many parts of the country and world. Due to factors like climate change, ticks are moving further into the northern hemisphere. Black-legged ticks (deer ticks) that transmit Lyme disease are most prevalent in places like New England and the Upper Midwest, but there are also ticks up and down the East and West coasts and reported cases of Lyme borreliosis in every state in the U.S. Of all the infectious diseases to be concerned about, Lyme and other tick-borne illness should be top of the list; anyone who spends time outdoors, particularly in tick-endemic places like wooded areas and tall grasses, is at risk for a tick bite that could cause a life-changing illness.
Many people ask, with Lyme disease rates rising, why is there no Lyme disease vaccine for humans? Let’s walk through the answer and talk about other ways to protect yourself against the insidious threat of tick-borne illness.
Lyme disease is contracted through the bite of an infected black-legged tick. When that tick bites a human or animal, it can transmit the Lyme disease bacterium, Borrelia burgdorferi, during the tick bite. Black-legged ticks can also transmit other disease-causing pathogens (for more information, see GLA’s Common Tick-Borne Diseases (TBDs) page.)
Common early symptoms of the bacterial infection Lyme disease can include an erythema migrans rash, joint pain, fever, fatigue, and swollen lymph nodes. If the infection isn’t treated appropriately, the Lyme disease bacteria can move throughout the body and brain, causing serious impairments such as Lyme carditis, Lyme arthritis, and nervous system symptoms like facial palsy, peripheral neuropathy, brain fog, and sleep disturbances. If diagnosed and treated early, Lyme disease can often be cured, but if not, the disease can become chronic and severely debilitating.
Although there are vaccines available to protect dogs from Lyme disease, there is currently no approved vaccine for regular use in humans.
Previous efforts to create an effective vaccine against Lyme disease in humans included one developed by SmithKline Beecham, LYMErix. This vaccine was approved by the U.S. Food and Drug Administration (FDA) in 1998, but it was discontinued due to concerns over side effects and low consumer interest (for more information, see the Time Magazine article “We Used to Have a Lyme Disease Vaccine. Are We Ready to Bring One Back?”)
Scientists are now working on new vaccine candidates. One being developed by Pfizer and Valneva (VLA15) builds on the science of LYMErix, targeting the outer surface protein A (OspA) of Borrelia burgdorferi. As described on the Pfizer website, “Blocking OspA inhibits the bacterium’s ability to leave the tick and infect humans. The vaccine candidate covers the six most common OspA serotypes expressed by the Borrelia burgdorferi sensu lato species that are prevalent in North America and Europe.”
Additionally, the University of Massachusetts Medical School’s MassBiologics is working on prevention technique using a human monoclonal antibody for pre-exposure prophylaxis (PrEP) against Lyme disease. PrEP with this monoclonal antibody would offer seasonal protection, likely involving a single annual shot administered at the start of tick season.
Before a vaccine can be approved for public use, it must undergo rigorous clinical trials to ensure its safety and efficacy. These trials explore safety concerns and study any adverse events in vaccine recipients.
Clinical trials for new Lyme disease vaccines are underway. Pfizer and Valneva’s VLA15 is currently in Phase 3 human trials. Their website notes that “The VLA15 candidate has demonstrated a strong immune response and had a favorable safety profile across all dosages and age groups in pre-clinical and clinical trials so far. No vaccine-related serious adverse events (SAEs) and no safety concerns were observed by an independent Data Safety Monitoring Board (DSMB).” If trials continue to go well, the VLA15 could be submitted for approval by the FDA in 2025.
MassBiologics PrEP has completed a Phase 1 trial and now must undergo Phase 2 and Phase 3 trials. If those are successful, PrEP could be submitted for FDA approval in 2024.[i]
Researchers at the Yale School of Medicine are also exploring a new vaccine with mRNA technology that would cause one’s skin to have an immediate reaction to a tick bite (by recognizing and reacting to tick saliva), so that someone could potentially remove the tick before it has the chance to transmit any pathogens.[ii] This type of vaccine would help prevent against all tick-borne diseases, while VLA15 and PrEP would only protect against Lyme disease.
While researchers work on clinical development of vaccines, the best methods of Lyme disease control are awareness and personal protection. If you spend time outdoors, you should wear insect repellent containing DEET or picaridin and avoid wooded areas and other spots where ticks like to live such as tall grass, beach grass, woodpiles, leaf litter, and stone walls. Due to climate change, the risk of tick-borne illness is increasing, so it’s very important to be Tick AWARE:
There is a long road ahead in the fight against Lyme disease, but there are promising signs of one day having an effective vaccine. Until that time, we need to continue improving awareness and research. Global Lyme Alliance is leading the charge to conquer Lyme and other tick-borne diseases.
[i] https://www.umassmed.edu/news/news-archives/2022/05/massbiologics-research-into-preventive-shot-for-lyme-disease-continues-to-move-forward/
[ii] https://www.aamc.org/news/lyme-disease-rise-why-there-still-no-vaccine
[ii]https://www.globallymealliance.org/blog/lyme-disease-and-joint-pain
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