Nose-Spray Vaccine Against Botulism Effective in Early Tests
Posted Jan 11 2009 2:53pm
A preclinical study found a new nasal spray vaccine to provide complete protection against a major botulism toxin, according to a study published today in the Nature journal Gene Therapy.
Botulism is caused by a bacterium, Clostridium botulinum, which produces toxins that cause paralysis and often death, as the muscles that control breathing fail. Out of an average of 145 U.S. cases each year, 65 percent are infant botulism (infants’ intestines, unlike adults, are vulnerable to spore-containing dust), 20 percent are wound botulism (bacteria colonizes the wounds of severely injured patients) and about 15 percent are food-borne (improperly stored food can harbor C. botulinum), according to the U.S. Centers for Disease Control and Prevention (CDC). Botulinum neurotoxins (BoNTs) have been designated Category A bioterrorism agents that pose a high risk to national security because they are deadly, easily prepared and could conceivably be spread by inhalation.
Researchers are working to design a botulism vaccine that adds a second layer of immune protection against exposure to BoNTs. When complete, it would prime the disease-fighting cells in mucous membranes lining the nose, those most likely to be exposed first, along with those in the blood. Standard vaccines, given by injection, prepare only the blood-based immune system to fight a given disease. Secondly, the hope is that a new, well-defined subunit vaccine will enable authorities to provide an effective vaccine without having to mass-produce the actual toxin, the hazardous first step in the manufacture of the current, stockpiled vaccine.