Simulations show health workers, not public, should obtain smallpox vaccinations.

2003 MAR 19 - (NewsRx.com & NewsRx.net) -- by Maria G. Essig, MS, ELS, senior medical writer - A simulation of various scenarios involving terrorist attacks using smallpox virus indicated that immunization of healthcare workers is likely to be worth the risks, but the benefits of immunizing the general public is unlikely to be worth the potential harm unless a national attack is probable, according to a report in the New England Journal of Medicine.

"The new reality of bioterrorism has led nations to reconsider smallpox vaccination, which has not been generally recommended since the elimination of the natural disease," said Samuel A. Bozzette and colleagues at the RAND Center for Domestic and International Health Security in the United States and the University of California at San Diego.

"The current policy may be appropriate, since the risk of natural infection is negligible, the complications of vaccination can be severe, and measures instituted after an outbreak have been effective in controlling the spread of disease. However, variola stocks could be hidden, coordinated lethal terrorist attacks have occurred, the taboo on biologic weapons has been broken, and a government facing military defeat might feel unconstrained in using a smallpox weapon," the researchers continued (A model for a smallpox-vaccination policy. N Engl J Med, 2003;348(5):416-425).

Using information garnered from literature searches and parameters estimated from smallpox outbreaks that occurred after World War II, the investigators developed potential terrorist attack scenarios.

Under conditions of infected patient and contact vaccination followed by isolation, 7 deaths (from smallpox or the vaccine) would occur if the virus were released from a laboratory, 19 deaths if the virus were spread via a human vector, 300 deaths if the virus were spread throughout a large building, 2,735 deaths in a low-impact airport ...