First-ever mRNA Vaccine Against Ticks

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Using mRNA technology, researchers at Yale University have developed a vaccine against ticks, offering protection against Lyme disease.

The United States reports almost 40,000 annual cases of tick-borne illnesses, such as Lyme disease. Moreover, these tick-borne diseases pose a danger to not just hikers but also farmers and all those who frequent the outdoors. Therefore, a team of Yale researchers have now developed an mRNA vaccine against ticks.

There are multiple tick-borne diseases, and this approach potentially offers more broad-based protection than a vaccine that targets a specific pathogen. It could also be used in conjunction with more traditional, pathogen-based vaccines to increase their efficacy.

Dr. Erol Fikrig, senior author

Vaccine Shows Success in Guinea Pigs

Repeated exposures to tick bites can cause some animals to develop tick immunity where the tick detaches from the skin soon after biting. Guinea pigs, rabbits, and cows all react this way on repeated tick exposure. However, one can not repeatedly expose people to tick bites for building immunity. Instead, the Yale researchers focused on inducing immunity using the tick’s saliva.

The Lyme disease pathogen, Borrelia burgdorferi, is present in the saliva of the black-legged tick Ixodes scapularis. Their saliva contains several proteins, but for the vaccine, the researchers focused on 19 separate proteins. The mRNA vaccine, called 19ISP, induces immunity by recognizing these 19 proteins.

When the team tested the vaccine on guinea pigs, they found that vaccinated pigs developed skin redness on exposure to infected ticks. The ticks did not feed on the animals and quickly detached. Thus, none of the immunized pigs contracted an infection. However, 60% of the non-vaccinated pigs developed a Borrelia infection. Furthermore, the ticks detached more quickly in the vaccinated group than the control group.

Although the mRNA vaccine was a success in guinea pigs, researchers have not seen a similar result in other animals. Therefore, before the technology can be adapted for humans, researchers plan to conduct further trials in other animals to better understand the differences in tick immunity.


Sajid, Andaleeb, et al. “MRNA Vaccination Induces Tick Resistance and Prevents Transmission of the Lyme Disease Agent.” Science Translational Medicine, vol. 13, no. 620, 2021, doi:10.1126/scitranslmed.abj9827.


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