The Ghost of Smallpox Past
Despite its being dead for 25 Years, the specter of a smallpox pestilence -- via terrorism -- haunts the public.
What is the Real Threat? continued...
Samuel A. Bozzette, MD, PhD, and colleagues at RAND Health Care and the VA San Diego Healthcare System, have looked at several plausible scenarios for smallpox emergencies. They aren't writing science fiction. It's a dead-serious effort to come up with cost-benefit numbers to guide public health readiness and response.
"How likely is a smallpox bioterror attack? That is a matter for the government to judge," Bozzette tells WebMD. "The president says the risk of imminent attack is low. And from scenarios we've analyzed, the range of complexity required to actually carry out these attacks varies quite widely."
In the worst-case scenario, mass public vaccination would save about 30,000 lives. But there's a catch. We prevent those "what-if" deaths at a cost of about 500 very real deaths from vaccine complications.
"Our study shows that in order for there to be a substantial advantage for mass vaccination of the public, we would need to be facing a significant threat of a very widespread attack," Bozzette says.
The surprising conclusion: Mass smallpox vaccination, either before or after a large-scale attack, won't do much net good. The reason lies in the nature of smallpox itself.
Nobody doubts that smallpox is a terrible disease. It kills some 30% of people who get it, and leaves many more terribly scarred for life. There's no drug that can cure the disease.
It's quite contagious but generally, direct and fairly prolonged face-to-face contact is required to spread smallpox from one person to another. Smallpox also can be spread through direct contact with infected bodily fluids or contaminated objects such as bedding or clothing. Rarely, smallpox has been spread by virus carried in the air in enclosed settings such as buildings, buses, and trains, according to the CDC.
It takes about 12-14 days for infection to incubate -- and by the time a person is ready to spread the disease, that person is very ill. Most cases are spread at bedside. That's why smallpox should be treated at home or in special facilities, not in hospitals.