Minutes later, officials declare that the country is under a terrorist smallpox attack. Panicked families swamp hospital emergency rooms nationwide.

The federal government makes immediate plans to inoculate 3.5 million people, but most of the emergency-response teams, including most emergency-room doctors, have not been vaccinated for the virus. Many do not show up for work, stymieing attempts to isolate the outbreak and adding to the growing death toll.

This scenario of unpreparedness is not fanciful, according to Michael H. LeRoy, a professor of industrial relations and of law at the University of Illinois at Urbana-Champaign. It reflects "a disturbing consensus among medical and national security experts" that, three years after the 9-11 attacks, federal policy has failed to prepare the nation for the possibility of bioterrorism through the deliberate spread of the variola (smallpox) virus.

Smallpox is highly contagious and kills about 30 percent of those infected. A scourge throughout most of human history, the virus in its natural state was eradicated in the United States by 1950. Smallpox vaccinations for the general public were ended in 1972.

"Why then so much alarm among experts?" LeRoy asked in a forthcoming article in the Emory Law Journal. One reason is that the virus, known to be stored in both a U.S. and former Soviet Union lab, could be weaponized in an aerosol form and released into a city block or large crowd.

"It spreads easily by normal human interaction," LeRoy said. Although the federal government does have large quantities of smallpox vaccine to inoculate the public, the virus could spread widely and rapidly among an unprotected population before those infected are diagnosed and put in isolation wards.

"After incubating for seven to 17 days, the first symptoms of smallpox appear: fever, tiredness, head and body aches, and sometimes vomiting. After two to four days, small red spots develop on the tongue and in the mouth before progressing to the face, arms, legs, hands and feet. The rash spreads over the entire body within another 24 hours. The contagious period is long, starting with onset of a fever and ending when the last scab falls off. This assumes a smallpox patient survives."

The second reason for alarm is the small number of emergency personnel who are vaccinated. As of July 31, 2004, only 39,379 of the 500,000 workers identified by the federal government as front-line responders have received a smallpox shot.

This low figure comes despite efforts by Washington and some state governments to persuade doctors and hospital personnel to be vaccinated voluntarily. The latest figures indicate that the volunteer program has virtually stalled -- only 25 new vaccinations were administered nationwide to "emergency responders" between May 1 and July 31, 2004, according to Web site of the Centers for Disease Control and Prevention.

"An ineffective vaccination policy for emergency doctors is the greatest hole in the nation's security," LeRoy asserted. He therefore recommends a concerted government push -- using direct economic incentives -- to overcome the widespread apathy to the smallpox threat and the overreaction by some people of the side effects from the vaccine.

Examining America's response to smallpox in the 19th century, the Illinois expert concluded that smallpox treatment was handled most effectively when doctors were given large enough cash payments to risk their own health to care for patients in pest houses and quarantined ships.

Today, cash incentives are less important to doctors than protection from skyrocketing malpractice insurance costs. The Swine Flu vaccination program in the 1970s was successful because a federal cap on medical liability encouraged vaccine makers and doctors to participate in a program that ran a small risk of injury from adverse reactions to the vaccine.

To similarly motivate bioterror responders, LeRoy proposes that Congress cap malpractice insurance for emergency-room doctors who agree to be vaccinated. "This approach would cause emergency doctors to link two risk assessments that they now make on an independent basis -- the probability of their adverse reaction to a smallpox shot and their preference for liability risks."

As an additional benefit, a cap on liability insurance could help reverse the national decline of emergency-room doctors, which further exposes the country to potential disaster in the case of a bioterrorist attack.

"If one profession is crucial to control smallpox, it is the emergency-room doctor. If that physician identifies a case two or three days before symptoms become obvious, a timely quarantine can occur. Public health plans can spring into action. Innumerable infections can be prevented."

In the aftermath of the anthrax attacks in 2001, the danger of a terrorist armed with smallpox received a flurry of attention in the media and by the Bush administration. In December 2002, President Bush announced a plan to encourage health-care workers to volunteer to get the smallpox vaccine. But neither the voluntary Bush plan nor the Smallpox Emergency Personnel Protection Act, passed by Congress in early 2003, has done much to improve the rate of inoculations.

"I am not proposing a grandiose plan to expand the government's current smallpox immunization program," Leroy said in an interview. "But I do wish to draw attention to the moribund state of the current immunization program and to suggest an idea to encourage vaccinations."

LeRoy's article, "Pox Americana? Vaccinating More Emergency Doctors for Smallpox -- A Law and Economics Approach to Work Conditions," is to be published in the winter 2005 issue of the Emory Law Journal.