New Lyme Vaccine Shows 75% Protection in Major Trial

Nearly half a million Americans get Lyme disease each year, but a breakthrough vaccine could finally turn the tide against the tick-borne illness.

Pharmaceutical companies Pfizer and Valneva just announced positive results from their phase 3 trial of a new Lyme disease vaccine. The shot showed 73 to 75 percent effectiveness at preventing infections in a study of 9,400 people across the U.S., Canada, and Europe.

The vaccine works differently than most shots you've had before. Instead of targeting bacteria inside your body, it goes after the culprit while it's still inside the tick.

When an immunized person gets bitten, the tick ingests antibodies from their blood. Those antibodies then kill the Borrelia burgdorferi bacteria inside the tick before it can spread into the person's bloodstream.

The trial included children as young as five and required four doses over about a year. Participants needed a booster shot before each tick season to maintain protection.

Lyme disease cases have been climbing for years as warmer temperatures expand tick habitats and lengthen tick seasons. More than 89,000 cases were officially reported to the CDC in 2023, though the actual number is likely much higher since many cases go undiagnosed.

The Bright Side

This vaccine reflects major improvements over LYMErix, an earlier Lyme shot that was pulled from the market in 2002 amid safety concerns and poor sales. The new version protects against six different bacterial variations instead of just one, covering the most common strains in North America and Europe.

Scientists also removed the component that people worried might cause joint pain in the original vaccine. While that link was never proven, addressing those concerns head-on shows researchers listened to patient feedback.

Martin Backer, an infectious disease physician at NYU Langone Health who tested the vaccine in children, says he's cautiously optimistic. Daniel Pastula, a neurologist at the University of Colorado, notes that while insect repellent and protective clothing help, most people don't consistently use these prevention methods.

The vaccine has been submitted to the FDA for approval. If it gets the green light, it could offer protection to millions who live in or visit tick-prone areas.

After years of rising infections and expanding tick populations, science is finally catching up to give us a powerful new tool against Lyme disease.