- Lyme disease can be debilitating; symptoms can range from mild to life-threatening.
- Two pharmaceutical companies, Pfizer and Valneva, are developing a vaccine to prevent Lyme disease in people ages 5 and up.
Mindi Weidow vividly remembers the moment she found her first tick.
She was getting undressed after a hike in woodsy Pennsylvania and found a tiny, pinhead-sized critter nestled near the bottom of her legging in the warm, snug spot where her pant leg met her ankle.
The tick had not burrowed too far into her skin yet, and she was able to pull it off without too much hassle.
Her father, however, was not so lucky.
Several years ago, a tick burrowed its way under his skin, and unleashed a nasty form of the borrelia bacteria into his blood. It wasn't until around two months later that lab tests confirmed he had Lyme disease. Weidow's father was then treated with antibiotics, but he still weathers arthritic flare ups and inflammation to this day, symptoms of what the CDC has deemed Post-Treatment Lyme Disease.
Now, Weidow is hoping that an experimental series of injections she's received might help her avoid the same fate. She is a participant in Pfizer's Vaccine Against Lyme for Outdoor Recreationists trial, or VALOR, the only late-stage lyme disease vaccine trial. If successful, the VALOR trial could herald a brand new way to prevent lyme disease, the widely underdiagnosed condition that may impact up to 500,000 Americans every year, and can lead to chronic, debilitating pain — and in rare cases, even death.
Lyme disease can impact the body and brain
Researchers estimate that roughly 15% of the world has had Lyme disease at some point. Symptoms can range from near imperceptible and flu-like at first, to life-threatening heart problems. The condition isn't always simple for blood tests to pinpoint, because people often test negative early on. Contrary to popular belief, there is not always a visible bull's-eye rash on the skin from a tick bite.
Once the borrelia bacteria have invaded the bloodstream, Lyme infections can spread from the skin to other areas of the body, impacting the immune system and leading to a wide array of non-specific symptoms. Patients with Lyme are often misdiagnosed with other conditions like chronic fatigue syndrome, also known as myalgic encephalomyelitis.
In addition to physical symptoms, Lyme can also cause neuropsychiatric issues. Studies have documented neurological issues associated with the disease, including paranoia, depression, visual disturbances, and suicidality.
Could four shots prevent Lyme disease for good?
Currently, there is no vaccine licensed to prevent Lyme disease in people, only shots for dogs. One human Lyme shot was briefly released years ago by vaccine-maker GSK. Although studies showed it was about 75% effective at stopping Lyme disease, it received a lukewarm public reception and was the subject of conspiracy-theory lawsuits, driving down sales and leading it to be quickly taken off the market.
But now there are skyrocketing numbers of Lyme infections in both the US and Europe, and an expanding range of tick territory due to climate change, making 2023 potentially the worst tick season on record yet. So Pfizer and its partner — French pharmaceutical-maker Valneva — have decided to try again.
Pfizer and Valneva's Lyme vaccine is a series of three initial shots plus one booster jab, delivered about a year later. There are about 6,000 trial participants testing out the vaccine across Lyme-prevalent areas of the US, as well as European countries where Lyme-carrying ticks live, including Germany, Sweden, and Poland.
The trial hasn't been without its hiccups. About half of the trial sites in the US were originally run by a private clinical research company called Care Access, but in February Valneva said in a statement that Pfizer was shutting those trial sites down early, due to violations of Good Clinical Practice (GCP) procedures. Care Access said in a statement at the time that it did not agree with Pfizer's decision, and that the company was sharing information with the FDA about the case "to ensure they have the facts." Pfizer declined Insider's request for comment on those specific events, but said in an email that "we will continue to enroll participants and carry out the study."
Fishermen, hunters, and biologists are already lining up for this vaccine
Weidow, who is enrolled at an independent trial site that is still up and running, received her first injection last August, then a second shot in November, and her third in April. She hopes it was all the real deal Lyme vaccine, but it's also possible she got fake placebo jabs.
She remembers feeling "a little bit of soreness" and "a little bit of fatigue" after her vaccinations, which her trial administrators say are some of the most typical side effect complaints, along with low-grade fevers. She'll go back next year for her final booster shot.
Then, the study investigators will wait to see what happens. If Weidow or her boyfriend, who's also enrolled in this trial, notice any new tick bites during the course of the study, which is set to continue through 2025, they've been instructed to keep the tick and bring it in for inspection. This is so vaccine researchers can determine whether or not the participants might've been exposed to Lyme-causing bacteria, and assess how well the vaccine may be working.
At the Pennsylvania clinic where Weidow gets her vaccines, roughly 200 trial participants from age 6 to over 90 have enrolled, with more expected to sign up this summer. So far, vaccine-takers have been a mix of outdoor enthusiasts like fisherman, paddlers, and hunters, as well as biology professors and landscapers. In short — almost anyone who lives, works, or has fun around ticks is eligible to try out this vaccine.
"Ticks are always a concern in our area," Dr. Alan Kivitz, who runs Weidow's trial at Altoona Center for Clinical Research, told Insider.
Weidow said she is looking forward to a day when, maybe, some of that apprehension could be resolved by a vaccine.
"For me personally, it relieves some of the stress and anxiety of making sure that you do that check the second you get home," she said.