Lyme disease vaccine: Pfizer, Valneva launch trials for first shot in 20 years

• Pfizer and Valneva have announced the start of phase 3 trials to test the efficacy of their new Lyme disease vaccine candidate, VLA15.
• Currently, there are no other vaccines available for this tick-borne disease.
• Lyme disease is on the rise globally, making the prospect of an effective vaccine highly anticipated.

Lyme disease is a growing problem, the debilitating condition is most commonly caused by the bacteria Borrelia burgdorferiwhich can be transferred by tick bites. Recent research revealed that 14.5% of the global population has, or has had, Lyme disease. The regions most affected are Central Europe, Eastern Asia, and Western Europe.

Lyme disease is on the rise in the U.S. The northeast’s black-legged ticks and the northwest’s less common western black-legged ticks — both of which carry the disease — are spreading across the nation. They can now be found in half of the country’s counties.

On August 8, 2022, pharmaceutical companies Pfizer and Valneva announced the beginning of phase 3 clinical trials for the world’s only Lyme disease vaccine, VLA15.

Testing VLA15 against Lyme disease

VLA15 is a multivalent vaccine, targeting the six most common serotypes of Lyme disease-causing Borrelia burgdorferi bacteria’s outer surface protein, OspA.

Pfizer and Valneva hope to enroll 6,000 participants ages 5 and older for the clinical trials. Trials will take place at 50 sites in places where Lyme disease is prevalent, including Finland, Germany, the Netherlands, Poland, Sweden, and the U.S.

“Obviously, any progress is really encouraging, and in phase 2 they showed that the vaccine was safe and raised the right kind of antibodies,” Dr. Peter Gwynne, post-doc scholar at Tufts University, who was also not involved in the vaccine trials, told Medical News Today.

“Phase 3 will see if those antibodies are actually protecting people from the infection,” he added.

Dr. Jayakumar Rajadas, assistant professor of research at Stanford University, who was also not part of the trial, pointed out that VLA15 will potentially be of the greatest use to people who have not yet been infected, as is often the case with vaccines.

“The reason for that,” Dr. Rajadas explained, “is because once Borrelia gets into the body of people, its code protein content changes dramatically, so they have less OspA, and more OspC, another very inflammatory protein. So, [Borrelia] has this polymorphic behavior of different protein expression in different environments.”

“So, it is very difficult to identify one vaccine candidate against this bacteria,” he told MNT.

Diagnosing Lyme disease

“Diagnosis relies on either the presence of a bullseye rash or laboratory confirmations by the way of serological tests,” Dr. Monica Embers, associate professor of microbiology and immunology at Tulane University, who was not involved in the trial, told MNT.

Dr. Embers said the diagnosis of Lyme disease can take a while.

“In at least 20% — but likely significantly more — cases, the rash doesn’t appear, looks different, or is in an area where it is unrecognized, such as the scalp. The serological tests are only 40-60% sensitive in early infection, so many cases go undiagnosed for long periods, which makes treatment more difficult,” she said.

“Patients can present with flu-like illness, fatigue, muscle and joint pain, cardiac abnormalities, and neurological symptoms. Facial nerve (Bell’s) palsy is sometimes observed, as is ‘brain fog,’ generalized cognitive impairment, and peripheral neuropathy. The infection is systemic (i.e., spread throughout the body), so many organ systems can be affected, making discrete clinical diagnosis difficult.”
— Dr. Monica Embers

“It can sometimes be difficult to discern [Lyme disease] from fibromyalgia, ME/CFS, ALS, and multiple sclerosis, given the similarities in signs and symptoms,” she added.

How to avoid Lyme disease

Staying away from black-legged or western black-legged ticks that can introduce Borrelia burgdorferi bacteria into the body is the best way to protect oneself from infection.

Identifying these ticks on the body can be difficult, since tiny young ticks are about the size of a poppy seed.

Dr. Gwynne elaborated on ticks’ behavior to MNT:

“Ticks will hang around and look to attach — the behavior is called ‘questing,’ which is fun — from places like long grass or low bushes.”

“So you can reduce the risk by steering clear of tall vegetation when you’re hiking, and clearing leaf piles from your yard, cutting back the grass, etc.,” he said.

“[I]f you’re out working or hiking in an area that has a lot of ticks, then long sleeves/pants [are] probably the best way to reduce bites. Pets are a big way for ticks to get into your house and then onto you, so keeping them off your pets is important as well.”
— Dr. Peter Gwynne

Dr. Embers suggested treating clothing with permethrin.

“Anecdotally,” said Dr. Gwynne, “they like places that are warm and damp, so they’ll tend to crawl to, [for example] hairlines, armpits, any crease or fold in your skin. These are also places that you might not see them, and they release an anesthetic, so you won’t necessarily feel the bite either.”

“That’s why the tick check is so important. You can’t check everywhere on your own (e.g., your back, behind your knees) so it’s always worth having someone else help you check for ticks if you can,” he added.

How to treat Lyme disease

Although Lyme disease can often be treated with antibiotics, persistent cases can be harder to resolve.

“Some areas where the bacteria is hiding are places that are not vascularized at all — they get into a lot of areas where there are not a lot of blood cells. Access for immune cells is very low,” said Dr. Rajadas, adding: “So, Borrelia can basically hide there, and it can move back into the blood cells, move to different areas, and cause the disease.”

However, he said, “Antabuse [Disulfiram] and Azlocillin are very good candidates for treating persistent borreliasis.”

“A lot of clinicians now [are] using Antabuse for a portion of persistent Lyme patients. The side effects are bad, and [just] 60% of the people are saying they are having better symptomatic relief. But still, that is the only one right now that they have.”
— Dr. Jayakumar Rajadas

Dr. Rajadas said Antabuse is generally used by clinicians as a means of deterring alcoholics from drinking.

Meanwhile, Azlocillin — not currently available in the U.S. — is available in China and, to a limited degree, in Germany.

Dr. Rajadas, who has been studying the drug, said:

“We think Azlocillin has a dual activity: Not only that it can kill persistent Borrelia, but it can prevent some of the pain-related symptoms and inflammation caused by the persistent bacteria.”

He noted, however, that a side effect of Azlocillin is blood thinning similar to aspirin.

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