Lyme disease, caused by bacteria that enters the body through the bite of an infected tick, is a growing problem, with reports of cases increasing and warming weather helping ticks expand their habitat. While a dog vaccine has long been available, the only human Lyme disease vaccine was pulled from the US market in 2002 due to lack of demand, leaving people to rely on bug sprays and tick controls. “There is currently no Lyme disease vaccine available for humans,” according to Health Canada. “However, there are clinical trials taking place in Europe and the US” These trials include Pfizer and French biotech company Valneva. They aim to avoid previous pitfalls in developing a new vaccine to protect both adults and children up to five years of age from the most common strains of Lyme on two continents. When the last vaccine was pulled from the market, Pfizer’s head of vaccines, Annaliesa Anderson, told The Associated Press that “there was no such recognition, I think, of the seriousness of Lyme disease.” Robert Terwilliger, an avid hunter and hiker, was first in line Friday when the study began in central Pennsylvania. He has seen many friends get Lyme and is tired of wondering if the next tick bite will make him sick. “It’s always a concern, you know? Especially when you’re sitting in a tree to hunt and you feel something crawling on you,” said Terwilliger, 60, of Williamsburg, Pa. “You have to be very, very careful.”
Canadian cases are under-reported
How often Lyme disease strikes is not clear. The US Centers for Disease Control and Prevention cite insurance records that suggest 476,000 people are treated for Lyme in the US each year. Pfizer’s Anderson put annual infections in Europe at about 130,000. In Canada, provincial public health units have reported 14,616 human cases of Lyme disease between 2009 and 2021. But the federal government says on its website that the numbers are underreported “because some cases are undetected or underreported.” Black-legged ticks, also called deer ticks, carry bacteria that cause Lyme disease. The infection initially causes fatigue, fever and joint pain. Often – but not always – the first sign is a circular red rash around the bite site. Registered nurse Janae Roland prepares either the vaccine or a placebo in Duncansville, Pa. The clinical trial will test the safety and effectiveness of the vaccine, called VLA15. (Gary M. Baranec/The Associated Press) Prompt treatment with antibiotics is vital, but it can be difficult for people to tell if they have been bitten, as some ticks are as small as a pin. Untreated Lyme disease can cause severe arthritis and damage the heart and nervous system. Some people have lingering symptoms even after treatment.
How the vaccine works
Most vaccines against other diseases work after people are exposed to a microbe. The Lyme vaccine offers a different strategy — it works one step earlier to prevent a tick bite from transmitting the infection, according to Dr. Gary Wormser, a Lyme specialist at New York Medical College who was not involved in the new research. It does this by targeting an “outer surface protein” of the Lyme bacteria called OspA that is present in the tick’s gut. It is estimated that a tick needs to feed on someone for about 36 hours before the bacteria can spread to its victim. This delay provides time for antibodies picked up by the tick from the blood of a vaccinated person to attack the germs right at the source. In small early-stage studies, Pfizer and Valneva reported no safety issues and a good immune response. The newest study will test the safety and effectiveness of the new vaccine, called VLA15. The companies aim to hire at least 6,000 people in Lyme-prone areas, including the northeastern US and Finland, Germany, the Netherlands, Poland and Sweden. Roland begins the process of making refrigerated doses of the new Lyme disease vaccine at the Altoona Clinical Research Center in Duncansville, Pa. (Gary M. Baranec/The Associated Press) Subjects will receive three doses of either the vaccine or a placebo between now and next spring’s tick season. One year later, they will receive a single booster dose. “We’re really looking at something that’s a seasonal vaccine,” Anderson said, so people have high levels of antibodies during the months when ticks are most active. Volunteers for the study can be as young as five years old and should be at high risk because they spend a lot of time in tick-infested areas, such as hikers, campers and hunters, said Dr. Alan Kivitz, head of one of the study sites in Altoona. Center for Clinical Research in Duncansville, Pa. In his own practice, Kivitz said that “not a day goes by that someone is either worried about Lyme disease, could possibly have Lyme disease.
Vaccination against bites
The new Pfizer-Valneva vaccine is made somewhat differently than its predecessor and also targets six strains of Lyme in the US and Europe instead of just one. The Pfizer study will take two seasons to get answers — but it’s not the only research into new ways to prevent Lyme. University of Massachusetts scientists are working on an alternative vaccine, shots of pre-made antibodies that fight Lyme. And Yale University researchers are in the early stages of designing a vaccine that recognizes a tick’s saliva — which in animal experiments triggered a skin reaction that made it harder for ticks to hang on and feed. Since different species of ticks carry many diseases besides Lyme, eventually “we’re all hoping for a bite prevention vaccine,” Wormser said.
