The Lyme Disease Vaccine Paradox.

Lyme disease causes a significant financial and health burden. Recent advances in developing new Lyme disease vaccines have renewed optimism that vaccination may serve as an additional strategy to reduce this burden. Vaccination alone will not address the broader relevant public health challenges posed by ticks. Our experience with prior Lyme disease vaccines suggests that even an effective vaccine would not fully reduce the incidence of human disease. Importantly, vaccination against Borrelia genospecies would not affect tick abundance or exposure risk. It would also not mitigate the transmission of other tick-borne pathogens that are proliferating in human-biting ticks. Tick-borne disease risk is shaped by the biological features of ticks and tick-borne disease agents, which differ from those of mosquitoes and mosquito-borne disease agents. Unique tick characteristics create opportunities for exposure and complicate prevention and post-exposure case management. In addition to infectious diseases, ticks are associated with non-infectious conditions such as tick paralysis and alpha-gal syndrome that will not be affected by a Lyme disease vaccine. The introduction of a Lyme disease vaccine should be viewed as one part of a broader risk management strategy. Emphasis must remain on clinical awareness and education for at-risk individuals. Personal protective behaviours, surveillance, and integrated tick control will also be essential to managing tick-associated health risks in both vaccinated and unvaccinated populations.