Doctors and nurses across the country hope to enroll a total of 480 people – 40 people at each of 11 sites – by the end of May in the study funded by the National Institute of Allergy and Infectious Diseases (NIAID).
For most of modern history anthrax has been a rare disease in people; it's most likely to infect farmers, veterinarians, and people who work with animals or animal products. That all changed more than two years ago, when several envelopes containing anthrax spores that bore the hallmark of sophisticated processing were mailed, emptying several office buildings, infecting several people, and spurring the search for a better vaccine.
While an anthrax vaccine now exists and is used primarily to protect military personnel, it requires a cumbersome routine – six shots over 18 months, with a booster shot every year thereafter – for the vaccine to confer protection. The current vaccine also causes a range of side effects.
Scientists are trying to develop a vaccine that works faster, with fewer shots and no annual booster, with fewer side effects. The vaccine under study, based on research by U.S. Army scientists and produced by California-based VaxGen Inc., requires two shots four weeks apart. Participants in the study will be monitored for one year as nurses and doctors record side effects and check the ability of the vaccine to rouse an immune response.
"If you're trying to immunize in the face of a threat, particularly if the infectious agent has already been released, a delay of 18 months until the vaccine is effective is a big problem," says John Treanor, M.D., professor of medicine and director of the Vaccine and Treatment Evaluation Unit at the University of Rochester. "That's just too long to wait."
In addition to a vaccine that might protect more quickly, doctors are trying to determine if the vaccine under development will have fewer side effects than the current vaccine because it's based on technology that results in a more purified product.
The work is the latest in a series of studies at Rochester aimed at protecting people against a potential bioterrorist attack. Two years ago the Rochester team, with the help of 170 volunteers from the Rochester area, showed that a diluted form of smallpox vaccine is just as effective as a full dose in protecting against the disease. And last year Treanor led a national team of scientists looking at how a booster shot affects the protection of people who have previously been vaccinated against smallpox. Results from that study have not yet been announced.