MONDAY, Aug. 30, 2004 (HealthDayNews) -- Scientists say they've moved closer to developing a powdered vaccine for anthrax that could be given through the nose, providing a safer, easier way to protect people from the potential bioterrorism weapon.
So far, the researchers have only confirmed that the needle-free vaccine appears to work in rabbits. But they're hopeful that future tests in animals and humans over the next two to three years will be successful.
"This is not a cure for anthrax, but may be a better means of protecting at-risk populations from infection," Vince Sullivan, a chemist at BD Technologies, said in a statement. His company is developing the vaccine in conjunction with the U.S. Army.
Researchers described the vaccine last week at the annual meeting of the American Chemical Society in Philadelphia.
Anthrax became a household word in 2001, shortly after the 9/11 attacks, when someone mailed infected packages to news organizations and government officials.
Anthrax spores occur normally in nature, particularly in dirt, but they usually infect few people in the United States. However, the inhalation form of anthrax is especially deadly, and experts say terrorists could potentially infect thousands of people with a small supply of the germ.
The anthrax vaccine protects most people who get it via six injections over an 18-month period. The vaccine hasn't been given to the general public; those who get it include members of the military, laboratory workers and people who work with animals.
Critics charge the anthrax vaccine is too dangerous, and controversy has arisen over whether soldiers should be able to refuse the shots.
New technology offers the chance to perfect the vaccine and make it easier for people to tolerate, said Dr. Henry Shinefield, co-director of the Kaiser Permanente Vaccine Study Center, in Oakland, Calif. Nasal vaccines in particular have become more popular in recent years as scientists developed ways to "deliver" antibodies -- germ fighters -- into the body in ways other than injections. Last year, the federal government approved the first nasal flu vaccine.
The body absorbs substances in many ways, including through nasal membranes, the skin or the intestines, Shinefield said. One possible benefit of nasal vaccines is that they may be more convenient than giving several shots, he said.
The researchers who are developing the nasal anthrax vaccine say it comes in a dry powder that can be administered into the nose without the aid of a nurse.
In tests, between 83 percent and 100 percent of vaccinated rabbits survived exposure to lethal doses of inhalation anthrax, according to the researchers. Researchers report that the existing vaccine provides a similar level of protection.
It's not clear how many doses of the nasal vaccine would be required to provide protection.
Even if the vaccine turns out to be effective, safety will be a prime concern, Shinefield said. "We're sophisticated enough now to know that you can't make assumptions. You want to be sure that every vaccine is not only effective but as safe as it can possibly be."
To learn more about anthrax, visit the U.S. Centers for Disease Control and Prevention.