Lyme disease is on the move. Once mostly a scourge in the Northeast, the disease spread to the Upper Midwest, and, in recent decades, clear to California and the Pacific Northwest. A kind of bacterial Manifest Destiny. It’s thought climate change is part of the reason. As the North American continent has warmed, the range of ticks has greatly expanded; the buggers prefer temperatures over 45 degrees and with high humidity (though tick species in dry California are also prevalent). That expansion has put them into greater contact with more people, and, as a result, the instance of Lyme disease in humans has doubled since 1991. According to the CDC, roughly 475,000 people are diagnosed with the disease each year.
A vaccine was tried and quickly abandoned, you might remember, in the late ’90s, after concerns about side effects and questions over efficacy. But in two years time, we might have a seasonal shot—not a vaccine, but still a prophylactic, that prevents Lyme.
It’s being developed at the University of Massachusetts in a program headed by Dr. Mark Klemper. The idea behind the shot is very clever—it kills the bacteria inside an infected tick’s gut the moment that tick bits a human. Unlike a vaccine, which prepares your immune system to make antibodies for an invader it recognizes, Dr. Klemper’s shot would introduce an antibody directly into your blood stream, which means your body doesn’t have to be infected first to realize it needs to fill the blood with antibodies to fight off the intruder, because the antibodies are already in your system. The tick bites you, your anti-Lyme antibodies are already in your blood, so the moment that blood gets into the tick, it kills the bacteria before it can replicate and infect you.
Klemper’s team have successfully experimented on mice (the paper they published about their results is available to read for free, here). Human trials began in early 2021, in tick-free Nebraska. Lyme disease tests are famously finicky, and to be sure they were drawing from a population that was almost certainly free from Lyme, they chose Nebraska. If a test subject came back with a positive result, for example, it would be difficult to be sure they caught the disease before or after the test.
So far, the tests look positive. Dr. Klemper explained in a recent article he wrote for The Conversation, that they’re mostly trying to determine how long the shots will protect a human against contracting the disease. For now, they expect one shot to last at least a full spring, summer, and fall, if not longer.
More tests confirming safety and efficacy are underway, and the hope is the shot will be available to the public by 2022 or 2023.
Top photo: Marcus Lewis/Unsplash