A team of researchers at Yale University have made progress in the development of a vaccination against ticks and tick-borne disease. Using the same mRNA vaccine technology used in the COVID-19 vaccine response, the team found that vaccinating guinea pigs reduced infection rates of Lyme disease.
Tick-borne disease rates in North America are increasing, with Lyme disease being the most prevalent. Early signs of Lyme disease consist of a rash and flu-like symptoms, although if untreated more severe symptoms develop. Almost 40,000 cases of the disease are reported annually in the US, but the actual number is estimated to be up to 10 times greater. Previous attempts to develop tick vaccinations have been generally unsuccessful, and commercial vaccines available for animals reduce tick numbers but do not prevent disease.
Repeat exposure to ticks can lead to the development of “tick immunity”, so this new vaccine aims to safely achieve immunity while bypassing the need for multiple exposures. Referred to as 19ISP, this new vaccine contains 19 different proteins found in tick saliva, simulating a bite. Once vaccinated, guinea pigs were exposed to ticks to examine the vaccine’s effectiveness.
19ISP combats ticks on two fronts. Firstly, it made the bites unusually inflamed and itchy, allowing for early detection and a higher chance of the tick being removed before disease spreads. When ticks were removed once the bite became inflamed, none of the vaccinated guinea pigs tested positive for Lyme disease while almost half of the non-vaccinated control group did.
Secondly, 19ISP reduces the number of time ticks spent feeding on the guinea pigs. While ticks typically feed for 3-5 days, after four days 80% of the ticks on vaccinated guinea pigs had stopped feeding. In contrast, only 20% had stopped on the un-vaccinated guinea pigs, showing that the vaccine decreases the amount of time the ticks were able to feed for.
By reducing tick feeding time and increasing detectability, 19ISP has the potential to combat numerous tick-borne diseases. Further studies are needed to understand its effect on these other diseases and the degree of protection in humans. However, this study is a promising step in the right direction to improving Lyme disease prevention.
