Rachel Salmond needed little prodding when her two oldest daughters had an opportunity to test what might become the first vaccine available for Lyme disease in two decades.
Salmond, a pharmacist at Charlton Memorial Hospital in Fall River, calls herself “very pro-vaccine.” Her daughters, Maggie, 11, and Julia, 9, participated in a study last year of Moderna’s COVID-19 vaccine. When Salmond recently heard that her family’s pediatrician was testing another vaccine, for Lyme, she was intrigued. Then her youngest daughter, 6-year-old Charley, was diagnosed with Lyme a month ago and couldn’t play softball for much of the summer.
“She had to go through two weeks of antibiotics, and, being a pharmacist, you know that’s a long time to take an antibiotic,” said Salmond, who lives in Freetown. “It was at least a week or more of treatment before she started to be herself again.”
Advertisement
Last Thursday, Maggie and Julia each received a shot at Pediatric Associates of Fall River as part of a late-stage trial in the US and Europe of a Lyme vaccine from the pharmaceutical giant Pfizer and a French biotech, Valneva. (Charley was ineligible because she was recovering from Lyme.) Researchers plan to recruit about 6,000 volunteers 5 years of age and older at study sites where Lyme is widespread, including eight Northeastern and Midwestern states, as well as Finland, Germany, the Netherlands, Poland, and Sweden.
The regional focus within the US won’t surprise parents. In New England, checking children for ticks after they play in wooded areas has become as much of a summer ritual for some people as watching a Red Sox game or eating a lobster roll.
The only trial site for the vaccine in Massachusetts so far is the doctors’ office where the Salmonds went, according to an online federal registry of clinical trials. Dr. Walter Rok, a pediatrician and clinical investigator at the practice, said parents are so interested in the study that he has told Pfizer he can easily find 50 to 100 children to participate.
Advertisement
“Each and every summer, we see about a dozen kids with Lyme,” said Rok.
No Lyme vaccine has been commercially available since 2002, when the British drug firm GlaxoSmithKline pulled one from the market after a controversial rollout. If successful, Pfizer says it could apply for approval from regulators in 2025.
The trial is one of several efforts underway to prevent the disease, which can initially cause fever, chills, headache, fatigue, and aches in the muscles and joints. If left untreated, however, Lyme can lead to a variety of serious debilitating symptoms, including arthritis, facial palsy, heart problems, and an inflammation of the brain and spinal cord.
In another study still in the early stage, scientists from the nonprofit biotech MassBiologics ― which is affiliated with the University of Massachusetts Chan Medical School ― have tested a vaccine alternative containing a laboratory-made Lyme antibody on 42 volunteers in the hopes of providing immediate immunity to the disease for up to six months. Although the protection would fade, it comes from a single fast-acting shot, a distinct advantage over vaccines that typically require a series of injections over several months, said Dr. John Sullivan-Bolyai, deputy director of clinical and regulatory affairs of MassBiologics.
Meanwhile, researchers from Yale University and the University of Pennsylvania are testing a potential Lyme vaccine in laboratory animals that uses messenger RNA to stimulate an immune response, the same technology behind the coronavirus vaccines of Pfizer and Cambridge-based Moderna. If the Lyme vaccine works, it would have to be tested in humans.
Advertisement
First identified in 1977 after a cluster of what initially appeared to be juvenile rheumatoid arthritis cases in Lyme, Conn., the disease is caused by the bite of deer ticks, which carry bacteria called Borrelia burgdorferi. For the bacteria to be transmitted, the tick must latch onto the skin for 36 to 48 hours, according to the US Centers for Disease Control and Prevention.
An estimated 476,000 people in the US are treated for the condition each year, based on insurance records, making it the most common disease spread by ticks, mosquitoes, or other insects in the country, according to the CDC. (That figure may be higher than the true number of infections because doctors sometimes presumptively treat for Lyme if patients appear to have symptoms.) About 70 to 80 percent of those diagnosed with Lyme report seeing a distinctive bull’s-eye rash around the tick bite, but plenty of infected people say they never did.
The standard treatment is two weeks of an antibiotic such as doxycycline or amoxicillin. Most patients who take medication early fully recover, according to the CDC. Nonetheless, scientists would rather prevent Lyme in the first place.
Climate change has fueled the spread of Lyme as ticks have made habitats in areas once too cold for them, such as parts of Canada, according to the US Environmental Protection Agency. Because ticks are about the size of a sesame seed, the parasites are easy to miss when they bite.
Advertisement
In 1998, the Food and Drug Administration approved the first Lyme vaccine, LYMErix, developed by what is now GlaxoSmithKline. Unlike most vaccines, which stimulate the immune system to create antibodies that ward off a germ, LYMErix prevented the bacteria from leaving the tick and infecting humans. The vaccine targeted an “outer surface protein” of the bacteria present in the tick’s gut. If a tick latched onto the skin of someone who was vaccinated, antibodies in the person’s blood would kill the pathogens inside the parasite.
A series of three LYMErix shots was nearly 80 percent effective in a late-stage study, according to researchers, and there appeared to be relatively few side effects. But the vaccine was hobbled from the start, partly because Lyme wasn’t regarded as a serious problem.
A member of a CDC advisory committee at the time denigrated the shot as a “yuppie vaccine” for people who “will pay a lot of money for their Nikes and their Esprit and shop at L.L.Bean’s” and “want a vaccine because they’re going to travel to Cape Cod,” Robert A. Aronowitz, a medical historian, wrote in 2012 in the journal Milbank Quarterly.
The vaccine hadn’t been tested on anyone younger than 15 before its approval. That frightened parents already alarmed by the 1999 withdrawal of a vaccine for rotavirus ― a severe form of diarrhea in young children ― that caused rare cases of bowel obstruction.
Advertisement
Some LYMErix recipients reported experiencing arthritis symptoms afterward, although the FDA found no link, according to a 2006 article in Epidemiology & Infection. A Philadelphia law firm filed a class action lawsuit on behalf of 121 vaccine recipients against LYMErix’s maker. In 2002, GlaxoSmithKline took the vaccine off the market, citing poor sales.
“The vaccine wasn’t pulled for safety issues or efficacy issues. It was just the wrong time,” said Sam Telford, an expert on tick-borne diseases at Tufts Cummings School of Veterinary Medicine who helped run a mid-stage LYMErix trial.
The vaccine from Pfizer and Valneva works essentially the same way but is likely to fare better, he said, because of the growth of a crucial market: “It’s mothers who are pissed off about having to check their kids for ticks every day.”
Unlike the earlier vaccine, the new one targets six strains of Lyme in the US and Europe. And researchers are testing it on children as young as 5 to determine whether it is safe and effective.
Participants in the trial will receive three shots within nine months and a booster dose a year later. Half of the volunteers will get the vaccine and half will get a placebo. Pfizer said the vaccine showed encouraging results in smaller studies.
Rachel Salmond, whose two oldest daughters got shots on Thursday, hopes the Pfizer vaccine works and wins approval.
“Just knowing that there might be one less thing I’d have to worry about as a parent would give me peace of mind,” she said.
Jonathan Saltzman can be reached at jonathan.saltzman@globe.com.