Whatever happened to the Lyme disease vaccine?

If you’re a dog, you’ve got lots of options for protecting yourself against Lyme disease, an often devastating illness spread by deer ticks. There are plenty of vaccines available at your local vet’s office, with names like Recombitek and Nobivac.

But us humans? Well, we’re out of luck because we don’t have a vaccine – at least not anymore.

For three brief years, there was a vaccine on the market, named LYMErix. But a combination of side-effect worries that some say were overstated, and some plain old disastrous PR paved the way for the vaccine’s demise.

Many who campaigned against the vaccine and who said they suffered side effects were happy to see it go. But others say the vaccine’s withdrawal was a tragic mistake that’s left the public without a valuable tool against what can be a devastating infection.

Infectious diseases specialist and vaccine researcher Dr. Stanley A. Plotkin has called the story of the Lyme vaccine “a public health fiasco.”

“The fact that there is no vaccine for an infection causing 20,000 annual cases (in the U.S.) is an egregious failure of public health,” he wrote in February, 2011, in a special Lyme-theme issue of the journal Clinical Infectious Disease.

Ten years after the vaccine’s withdrawal, Dr. Allen Steere, the key researcher behind it, is philosophical about the now-almost-forgotten vaccine.

“I do feel it’s a shame that we have a safe and effective vaccine and people cannot get it,” Steere said in a phone call from his office at Massachusetts General Hospital, in Boston.

“And it’s really the only infectious disease that I know of for which there is a safe and effective vaccine and it is not available who wants it.”

Steere not only helped discover Lyme disease in 1977 in the small town of Lyme, Conn., the rheumatologist has made the illness his life’s work and helped figure out how to create a vaccine against it.

LYMErix was unique among vaccines because it worked in such an unusual way. Unlike most vaccines that compel the immune system to create antibodies to fight a germ, this vaccine worked by immunizing the disease’s “vector”: the tick.

LYMErix would enter the tick as it fed on a human, which is often a full-day process. The vaccine neutralized the Lyme bacteria (B. burgdorferi) inside the tick‘s gut, thus blocking it from entering the human.

After three doses, studies showed the vaccine was effective in about 78 per cent of patients – far from a perfect rate, but better than many seasonal flu vaccines.

There were some questions about how long that effectiveness would last. Because the bacteria were killed inside the tick, vaccinated people didn’t develop their own immunity.

Steere said they were hoping that post-market testing would answer whether booster shots would be needed.

"But because the vaccine was withdrawn from the market, it was never really worked out how frequently the boosters would need to be given,” Steere said.

When LYMErix was approved by the Food and Drug Administration in December, 1998, many leapt at the chance to get vaccinated. Even though the cost was relatively high, sales that first year were brisk.

But within a year, everything began to turn.

A number of people came forward to say they had experienced strange side effects from the vaccine, or had developed arthritis shortly after their vaccination. Soon, news outlets were running stories on people claiming to be vaccine victims. Groups of patients began to band together, threatening to sue the manufacturer.

By 2001, the CDC and the FDA felt compelled to review the vaccine. By then, more than 1.4 million doses had been distributed in the U.S. A total of 905 people had reported reactions, most of them mild, though about 7 per cent were considered serious.

The FDA concluded there was no evidence that the vaccine had caused any serious reactions, nor that the rate of problems was any higher than with any other vaccine. It gave LYMErix the continued green light. But by then, the public was scared.

Looking back now, Dr. Steere said it may have been a finding from his own team that stoked the fears of those who rallied against the vaccine.

He explained that questions emerged in initial testing about whether a certain segment of patients might be sensitive to a protein in the Lyme bacteria, which triggered autoimmunity and arthritis. That protein was the one used in the vaccine.

“So it was something we wanted to look at carefully during phase 3 study,” he said.

“And we did not find examples of arthritis being triggered by the vaccine in that study.”

Indeed, later studies found no evidence that vaccine recipients developed arthritis at rates any higher than those taking placebos, nor at higher rates than the general public.

Nevertheless, those initial worries were picked up by what Steere called “the Lyme disease counterculture,” who insisted that vaccination had caused them health problems.

“It was questionable whether they even had Lyme disease, but they felt it made them worse,” he said.

Once the groups started threatening lawsuits, GlaxoSmithKline decided that the declining sales did not justify the money they’d need to defend themselves against the lawsuits. In February 2002, the company decided to withdraw the vaccine.

Much has been written about why the public, who initially warmly embraced the vaccine, turned so strongly against it. LYMErix is still the only fully approved vaccine to be withdrawn because of low public demand even amid a continually high rate of disease.

Steere doesn’t believe that any attempts to clear up confusion about the vaccine’s safety would have helped save it.

“Even if the manufacturer had launched some kind of campaign to dispel myths, it wouldn’t have much of a difference. They tried but they were just overwhelmed by the threat of class action lawsuits,” he said.

Today, Lyme disease continues to spread. Researchers with the Public Health Agency of Canada say established deer tick populations are now in southeastern Quebec and Ontario, southeastern Manitoba and parts of New Brunswick and Nova Scotia. In the U.S., the number of new Lyme cases is still growing.

And no vaccine maker in either country seems interested in trying again to market a new vaccine or perfect and reintroduce the old one. Another vaccine maker, Pasteur Mérieux Connaught, created and tested its own vaccine but decided not to go forward with licensing after watching what happened with LYMErix.

Nevertheless, Steere is hopeful that one day, a new and even better vaccine will be created.

“I continue to hope that there will become a vaccine for Lyme again,” he said.

He said science has a better understanding now about B. burgdorferi, the bacteria that cause Lyme disease. There’s also better knowledge about why some people develop arthritis long after a Lyme infection has been cleared from their body.

Steere said a vaccine maker in Vienna, Baxter Bioscience, is working on a vaccine though it’s unclear whether it could ever be used here, since Europe has different Lyme strains. Pasteur Merieux Connaught is also still working on new Lyme vaccines.

But some, such as Mayo Clinic vaccine expert Gregory Poland, say the legal and economic environment here in North America is still too “unfavourable” for any vaccine maker to think about launching a new Lyme vaccine here again.

Steere hopes that will one day change. The threat of Lyme disease is just as bad as it was 10 years ago, if not worse, and people are going to “have to think more about vaccination as a potential way of dealing with that threat,“ he said.

“The problem of Lyme disease is not going away.”