Pfizer is trying to bring a Lyme disease vaccine back to market 20 years after the last one was withdrawn

We could be on the verge of a first in decades: the development and launch of a tick-borne Lyme disease vaccine.

Summer is a time to enjoy the great outdoors, especially shady grassy areas where you can lie down and enjoy the weather. But it’s also that time of year when pesky but very dangerous critters hide in that very grass: black-legged ticks.

Not only is their bite very dangerous and removing these insects is extremely troublesome, but they also carry a very dangerous pathogen that they can spread through bites, causing Lyme disease. Although it can be treated with antibiotics when detected, some cases of Lyme disease are antibiotic-resistant and others go undiagnosed. In these patients, or in those whose infection is left untreated, the disease can cause severe symptoms, including loss of facial mobility.

The incidence of this infection is increasing worldwide, and access to a vaccine against the disease could help drastically reduce incidence and protect public health. Pfizer and the French pharmaceutical company Valneva only want to bring such a vaccine to the market.

No to Lyme

“With rates of Lyme disease rising around the world, it’s more important to offer people a new way to protect themselves from the disease,” said Annaliesa Anderson, Pfizer’s director of vaccine development, in a press release. “We’re really looking for something that’s a seasonal vaccine.”

The two companies are starting a late-stage pharmaceutical trial with 6,000 participants. This will test the vaccine’s ability to protect people from the disease and, if successful, could lead to the first approved vaccine option against Lyme disease since 2002. It would also be our only available such option: the previous vaccine, Lymerix, was withdrawn from the market by its manufacturer due to poor sales, despite being hailed as a major public health advance.

Participants in this study include adults and children ages 5 and older. These will be recruited from 50 locations where Lyme disease is endemic, such as Finland, Germany, the Netherlands, Poland, Sweden and the United States. Everyone will receive three doses of vaccine candidate VLA15 or a placebo, followed by a booster shot or another placebo.

Small early-stage studies showed that the vaccine candidate did not pose any safety problems and that it elicited a good immune response in participants. If successful, the current trials would pave the way for regulatory approval of the vaccine in Europe and the US by 2025.

Today, cases of Lyme disease have been recorded in every U.S. state, with approximately 476,000 of its citizens treated for the disease annually, according to the CDC.

Early symptoms include skin rashes, fever, chills, headache, fatigue, muscle and joint pain, and swollen lymph nodes. If the disease is detected, it can be treated quickly and quite effectively with antibiotics. Even so, infections can cause permanent damage to joints or cause facial paralysis or sagging. Between 10 and 20% of treated patients continue to experience joint pain, memory problems and fatigue for at least six months. About 1% of cases can result in Lyme carditis, which is caused by the bacteria reaching the heart. And while rare, Lyme can be deadly — the CDC states that 11 fatal cases of Lyme carditis were reported between 1985 and 2019.

The disease spreads through the bite of blackleg ticks. These insects burrow headfirst into the skin in hard-to-see places like the groin, armpits, or scalp. Although the bacteria are transmitted through their bites, a tick must remain attached to the body for 36 to 48 hours or more before the bacteria can be transmitted. There’s no data to show it can then spread from person to person or from pet to person — although pets can bring ticks into the garden or home with the pathogen.

Lyme disease is a growing problem. The warming climate is allowing ticks to expand their habitat and cases are increasing as a result. Veterinary vaccines against Lyme disease are already in use, but so far people have had to rely on bug spray and their own vigilance to ward off ticks.

The Pfizer study spans two tick seasons. Meanwhile, University of Massachusetts scientists are also working on a vaccine alternative, shots of ready-made antibodies to fight Lyme disease.