WASHINGTON (AP) _ Leaving smallpox vaccinations up to individual Americans could result in many more deaths in the event of terrorist attack, according to a study.
The result could be an increase of between 22 percent and 54 percent in mortality in case of a smallpox attack, according to a mathematical model developed by U.S. and Canadian researchers.
Currently the Bush administration has mandated smallpox vaccinations for 500,000 military personnel and is seeking voluntary vaccination of millions of medical and emergency personnel across the country, though the civilian program has lagged.
The research team led by Chris T. Bauch at McMaster University in Hamilton, Ontario, used game theory to estimate the share of the general population that would seek vaccination under a voluntary program _ about 19 percent.
The findings are reported in Monday's online issue of Proceedings of the National Academy of Sciences.
The team noted that vaccination campaigns have often met resistance from people concerned about side effects.
If the perceived threat of terrorism is low, the percentage of the population protected from the disease falls, creating a situation where it would be easier for an epidemic to spread.
``On the one hand, voluntary vaccination does not protect the public as it should. On the other hand, imposing mandatory vaccination to group-optimal levels arguably violates civil rights,'' the researchers concluded.
They recommended appeals to public spiritedness.