For immediate release: July 17, 2007
GALVESTON, Texas - Researchers at the University of Texas Medical Branch at Galveston are testing a new vaccine for smallpox, which may cause fewer side effects than the current vaccine. The goal is to find the fastest, safest protection from this deadly virus in the event of a bioterrorist attack.
The existing vaccine, Dryvax, has been licensed and used for decades and is given to U.S. soldiers stationed in some areas overseas. It has also been used in the first responders campaign that was put in place following the attacks on 9/11. However, in some individuals it causes rare and serious side effects, such as inflammation of the heart and brain. The trial will compare Dryvax to the newer vaccine, Imvamune, which has shown to have fewer side effects in preliminary studies.
The trial will test various dosing schedules to determine the most rapid and effective immune response to protect against smallpox. Neither of the two vaccines that are being studied can give someone a smallpox infection because they do not contain the smallpox virus.
Dryvax may take up to four weeks to give full protection against smallpox. However, early studies of the new vaccine Imvamune indicate it may provide a more rapid immune response. Dryvax also cannot be administered to people with skin conditions such as eczema, those with immune problems or those who share a home with these individuals, which means as many as 40 percent of the U.S. population might be ineligible to receive the existing vaccine.
"We're very pleased to be adding this to the biodefense work we are doing at UTMB," said Dr. Christine Turley, principal researcher.
"This is about public health protection. How do we protect the country if we needed to? We know Dryvax is not a completely harmless vaccine. The side effects are rare, but they still occur," Turley said. "We would like to have a safer vaccine. We have an obligation to minimize the risks that we are asking the military and other first responders to take for the rest of us."
Smallpox was officially declared eradicated by the World Health Assembly in 1980, but the virus exists in a few highly regulated laboratories in the world. Given the concerns about global terrorism, experts worry that the smallpox virus may be used as an agent of bioterrorism. Smallpox may kill up to 30 percent of those infected and can be contagious several days before development of any rash.
According to Turley, even one case of smallpox would be a public health emergency, and complex national planning has occurred to address this possibility. There is no effective treatment for smallpox, so vaccination remains the best option for first responders and the military.
UTMB is screening volunteers for the vaccine trial. The study is sponsored by the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health. Other institutions participating in the trial include Saint Louis University, University of Iowa, University of Maryland, Duke University, University of Rochester and University Hospitals of Cleveland.
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