Yale University researchers have developed an mRNA vaccine against ticks that could help prevent Lyme disease. This is a debilitating chronic condition caused by the bacteria Borrelia burgdorferi, which enters the body through the bite of infected black-legged ticks. If not promptly treated, the infection can spread to the joints, nervous system, and the heart, causing a lifetime of severe health issues.
Researcher Erol Fikrig led a team that created the blueprints for the experimental Lyme disease vaccine called 19ISP, which trains the immune system to identify a panel of 19 proteins found in the saliva of ticks. The research is featured in the journal Science Translational Medicine.
Fikrig and colleagues then tested their vaccine in a guinea pig model of Lyme disease. When vaccinated animals were bitten by ticks, they developed itchy hives, which was a clear sign that the immune systems were responding to the tick salivary proteins. Interestingly, ticks detached from the skin of vaccinated animals much faster—a good thing, considering that it takes about 36 hours for ticks to transmit the Lyme disease-causing bacteria.
Promisingly, none of the vaccinated animals bitten by infected ticks developed Lyme disease, whereas half the unvaccinated animals did.
Fikrig predicts that the mRNA vaccine will have a similar mode of action in humans, causing redness and itching at the bite site, providing a red flag that a tick has latched on to the skin. Presently, tick bites often go unnoticed, as the bites are painless. Even without removing the tick, the immune response triggered by the vaccine should cause the tick to naturally detach before it gets a chance to transmit the pathogenic bacteria.
19ISP is not the only Lyme disease vaccine currently in development, but it’s the first to target tick salivary proteins (and not the Lyme disease-causing bacteria itself). One benefit of this novel approach is that it may also help shield against other tick-borne diseases such as anaplasmosis and babesiosis.
Estimates say that around 476,000 people are diagnosed and treated for Lyme disease in the United States. In the absence of a vaccine, health authorities suggest that reducing exposure to ticks is the best defense against Lyme disease. This includes avoiding areas with high grasses or bushes and keeping pets and yards tick-free.