Pfizer and Valneva have recently announced later-stage studies into a new vaccine against Lyme disease, which, if eventually approved, would make it the first vaccine to target the tick-borne disease in decades.

VLA15, as the vaccine candidate is known, has so far shown promise in both adults and children, as well as “acceptable safety and tolerability profiles” for both groups, Pfizer and Valneva announced. VLA15 will work by blocking a tick’s ability to transfer Borrelia burgdorferi bacterium — which causes Lyme disease — to its human host.

Clinical trials have recently entered Phase 3, which involves 6,000 participants — age 5 and up — in the United States and five other European countries where Lyme disease is regularly reported among the population.

“With increasing global rates of Lyme disease, providing a new option for people to help protect themselves from the disease is more important than ever,” said Annaliesa Anderson, Ph.D., the senior vice president and head of vaccine research and development at Pfizer, in a news release issued last week.

But vaccine candidate VLA15 — if shown to be safe and effective — likely won’t be available to the public for years, Pfizer estimates. When the final clinical trials are completed, the drug company is aiming to “potentially” submit an application to the Food and Drug Administration (FDA) by 2025.

This may come as frustrating news as Lyme disease continues to affect a growing number of Americans — and especially those living along the Northeast, Mid-Atlantic and Upper Midwest regions where 90% of cases are reported, according to data from the Centers for Disease Control and Prevention (CDC).

Confirmed cases of Lyme disease reported to the CDC have climbed over the past two decades, from somewhere between 16,000 and 17,000 per year in the late 1990s to anywhere between 22,000 and 30,000 in the mid-to-late 2010s. When probable cases are factored in, the CDC estimated close to 40,000 or more annual cases in recent years.

But those are just reported cases. Recent estimates indicate that cases are often underreported, and the number of Americans treated for Lyme disease annually is actually “closer to 476,000,” the CDC notes. (That figure is likely an over-estimate, the agency notes, as some treatments are administered as a precaution for patients who may not actually have it.)

One major reason for the uptick in cases, the CDC reports, is that the ticks that transmit Borrelia burgdorferi bacterium have “expanded their geographic range.” In fact, since the late ‘90s, the number of U.S. counties considered “high-risk” for Lyme disease — particularly in the Northeast and Upper Midwest — have increased by more than 300%, the agency said.

“They are now routinely found in places they weren’t seen 20 years ago,” the CDC notes.

There was also a vaccine previously available for Lyme disease — LYMERix — though it was discontinued by SmithKline Beecham (now GlaxoSmithKine) in 2002 due to declining sales and concerns over side-effects.

Still, the pharmaceutical companies behind VLA15 are hopeful the new candidate will be embraced when, and if, it becomes available in several years’ time.

“Lyme disease continues to spread, representing a high unmet medical need that impacts the lives of many in the Northern Hemisphere,” said Juan Carlos Jaramillo M.D., the Chief Medical Officer of Valneva, in last week’s news release. “We look forward to further investigating the VLA15 candidate in Phase 3, which will take us a step closer to potentially bringing this vaccine to both adults and children who would benefit from it.”