The LYMErix vaccine used lipidated recombinant OspA (outer surface protein A) adsorbed to an aluminium hydroxide adjuvant in order to trigger an immune reaction when the vaccine was injected into the recipient’s arm. The antibodies to OspA created following this vaccination were not intended to fight the infection in the host’s body but aimed to travel into the tick’s gut where th B.burgdorferi s.s. usually reside prior to transmission to the host as feeding progressed. During the development of this vaccine it was not known that several ticks already have significant levels of bacteria such as B.afzelii in their saliva, making transmission more likely to occur in a shorter period of time. Nevertheless, the intention of the LYMErix vaccine was to prevent the B.burgdorferi s.s. from ever actually infecting the host.
Clinical Trial Results
Phase I and II trials found the vaccine to be safe in humans, and a Phase III trial was begun in 1995 under the leadership of Allen Steere, the doctor credited with recognizing Lyme disease. Nearly 11,000 healthy patients were given either a placebo or the vaccine during this trial, with injections at 0, 1, and 12 months. The Phase III trial published effectiveness rates of 49% in preventing Lyme disease in the first year, with this rising to 76% in the second year after all three injections of the vaccine. Serological testing appeared to show that those patients who did go on to develop Lyme disease did so due to vaccine failure, with antibody titers found to be significantly lower than in those individuals seemingly protected from the disease developing. Those patients vaccinated with LYMErix are unlikely to still be protected with the CDC (Centers for Disease Control) advising patients that the effects of the vaccination dissipate over time.
A class action lawsuit was brought against the manufacturer Smith Kline Beecham in 1999 claiming that those given the LYMErix vaccine were not warned about the possible consequences, particularly if they had a predisposition to autoimmune conditions and if they were already infected with Borrelia bacteria prior to vaccination. Many patients contended that they had contracted an untreatable form of autoimmune arthritis following the vaccinations with symptoms worse than they might have been should the patients have developed Lyme disease itself.
The case was settled in 2003, after LYMErix was removed from the market in 2002, with the manufacturer (now GlaxoSmithKline) paying attorney fees and costs but granting no compensation to the patients. Their main aim appeared to be removing the vaccine from the market rather than achieving a significant payout for the plaintiffs. Although the company maintains that LYMErix was withdrawn for financial reasons rather than as a result of safety concerns, the vaccine cannot be reissued without FDA-approved changes to the label and it appears that GSK have little intention of getting their fingers burnt twice. Investigation into a Lyme disease vaccine for Europe, and also work by a Canadian company into vaccines for Lyme disease was also scrapped following the LYMErix debacle.
The Future of Lyme Disease Vaccines
Vaccines have progressed since LYMErix, with testing procedures also improving in order to aid clinicians in assessing an individual’s response to the vaccine. Lyme disease vaccines for dogs have been available since the 1990s although many veterinarians are beginning to warn of the dangers associated with these in contrast to the low risks of treatment of Lyme disease with antibiotics should it occur. No human vaccine for Lyme disease has been brought to the market since LYMErix’s withdrawal, possibly due to a reluctance by pharmaceutical companies to face similar anger and contention.
The understanding of the role of OspA, OspC, and OspF in disease progression has been significantly advanced in recent years. Vaccines using a combination of an attack against the spirochaetes themselves, along with the protein in the ticks’ saliva which facilitates infection, are now the main focus of research into a Lyme disease vaccine. Meanwhile, incidences of the condition continue to spread, with a 3% infection rate thought likely in some tick-endemic areas of the US. As the disease continues to spread, warnings about being tick-aware become more and more essential and, if there is one thing that Lyme disease history tells us, this condition is complicated, both medically, and politically.
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