Lyme disease vaccine shows over 70% efficacy in phase 3 trial
Not perfect but good enough
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Despite falling short of its primary statistical goal in a
phase 3 randomized controlled clinical trial, in part because fewer than
expected Lyme disease cases were reported during the study period, the vaccine
showed about 70% to 73% efficacy in preventing confirmed Lyme disease after a
four-dose series. In a secondary analysis, the vaccine did meet the statistical
goal.
The vaccine, being developed by Pfizer and Valneva, was
studied at sites in areas of high Lyme disease incidence in the United States,
Canada, and Europe.
Pfizer said the reduction in infections is “clinically
meaningful” and indicated that the companies will submit the vaccine for
regulatory approval. If approved, it would be the first Lyme vaccine available
for humans in more than two decades.
Vaccine blocks bacteria from leaving the tick
The new vaccine candidate, known as PF-07307405 (LB6V), is a
multivalent protein subunit vaccine that targets the outer surface protein A
(OspA) of Borellia burgdorferi bacteria. When a person is
vaccinated with LB6V, the body creates antibodies that are ingested by the tick
as it feeds on the vaccinated person.
When the antibodies bind to OspA inside the tick, it
prevents the bacteria from leaving the tick and entering the human bloodstream.
The vaccine is designed to protect against the six most common versions of OspA
found in Lyme-causing bacteria in North America and Europe.
The vaccine prevents the bacteria from leaving the tick
and entering the human bloodstream.
“Lyme disease can cause potentially serious
consequences—where individuals and families face symptoms that can disrupt
daily life, work, and long-term health—and there is currently no vaccine
available,” Pfizer Senior Vice President and Chief Vaccines Officer Annaliesa
Anderson, PhD, said in a statement. “The efficacy shown in the VALOR study of
more than 70% is highly encouraging and creates confidence in the vaccine’s
potential to protect against this disease that can be debilitating.”
Rising vaccine skepticism may cast shadow
A previous vaccine, LYMERix, was
approved for use in people in 1998. Research conducted at that time suggested
LYMERix reduced infections by as much as 76%, and no causal link between the
vaccine and adverse events was ever established. But reports of adverse
reactions began to circulate in the press, and safety concerns tanked sales.
GlaxoSmithKline (now GSK) pulled the vaccine from the market in 2002 because of
low consumer demand.
The new Pfizer/Valneva vaccine is likely to face increased
scrutiny. As head of the Department of Health and Human Services, Robert F.
Kennedy Jr. has pushed an anti-vaccine agenda, dismantling federal immunization
advisory boards and rebuilding them with vaccine skeptics and slashing the
number of recommended childhood vaccines. (A federal judge recently blocked the
Trump administration from implementing its proposed changes to the childhood
vaccine schedule.)
Moderna is currently developing an mRNA-based Lyme vaccine
candidate. Recruitment for the phase 1/2 trial is ongoing.
A Lyme disease vaccine for dogs has been
on the market since 2016.
Roughly 476,000 patients are diagnosed
as having Lyme disease each year in the United States. The condition is caused
by B burgdorferi spirochetes, which are transmitted to humans
by certain Ixodes species ticks known as black-legged or deer
ticks.
Infection can affect multiple organ systems and is usually
treatable with antimicrobial drugs. When not caught early and treated, Lyme
disease can cause serious, long-term health issues such as heart problems,
chronic inflammation and joint pain, and neurologic problems.
In the United States, most Lyme disease cases occur in the
Upper Midwest and along the northeastern seaboard. Ticks carrying the B
burgdorferi spirochetes are also found in parts of Central and
Northern Europe. Lyme disease is considered the most common vector-borne
illness in the Northern Hemisphere.
