MONDAY, April 15, 2002 (HealthDayNews) -- An unexpected surge in cough medication sales could give public health authorities an early warning of an anthrax outbreak after a bioterrorist attack.
Researchers in Pittsburgh have created a statistical model that would set off alarm bells if the sale of such medications unexpectedly passed a certain threshold, which they say might give officials warning within the first crucial days of an outbreak.
But another expert says the system would most likely serve as a secondary confirmation of reports from hospitals, which would most likely be the front line of such an attack.
Anthrax is an acute infectious disease caused by a spore-forming bacterium, which can infect the lungs, the skin or the intestines. Symptoms of the early stages of inhalational anthrax resemble the common cold, but this can progress to severe breathing problems, shock, and even death.
The study appears in tomorrow's issue of the Proceedings of the National Academy of Sciences. Although the research began long before the events of September 11, the findings have taken on an added sense of urgency following the rash of anthrax outbreaks that left many Americans wary of powdered substances and mail in general.
Senior investigator Stephen Fienberg, a professor of statistics at Carnegie Mellon University in Pittsburgh, analyzed a confidential database from a local grocery store chain to try to find useful information from its records of over-the-counter medication sales.
Keeping in mind that people might try to self-medicate for certain early symptoms of anthrax exposure, Fienberg looked for data on sales of painkillers, cough medications and flu and stomach ailment drugs. He eventually focused on medications that relieve cough.
The report suggests that a spike in cough medication sales twice that of average daily sales is sufficient to suggest a potential problem to public health officials.
The researchers tested the model using data from a 1979 outbreak of anthrax in Sverdlovsk, Russia, and found that the system would flag a 36 percent increase in sales within the first three days of an outbreak.
But Christopher Laxton, the executive director of the Washington, D.C.-based Association for Professionals in Infection Control and Epidemiology, suspects that medical professionals from hospitals would be the first to warn public health officials of a potential anthrax outbreak.
"We think hospitals would be the front line, because when people start feeling really sick, they don't go to their family doctor, they go to the emergency room," says Laxton. However, he says that family physicians may also see an increase in patients asking for antibiotics.
Still, Laxton says that sales of cough medicines would be "a useful validation."
"The difficulty is that a number of potential bioterrorist agents mimic symptoms of common ailments, most particularly the cold and the flu," says Laxton. "The fact that there's a spike in OTC cough and cold medicines can be put down to any of those things just as easily as they could be to anthrax, smallpox, plague and so forth."
But because a run on cough medications could reflect other outbreaks, like the flu, Fienberg says that the system has to look at seasonal cycles of purchases and whether an increase in medication sales simply mirrors a rise in total sales volume. Fienberg says that his team tried to compensate for many of these variables, but admits that they probably didn't account for all of them.
But he stresses that this statistical model is meant to give public health authorities extra information rather than sending up red flags and causing panic. "The purpose is to help the public, not alarm the public," he says.
Fienberg points out that in the future, this system would most likely include factors other than cough medications. "You could think of absences from school as an example," he says.
But Fienberg notes that the system would only work in a situation involving a large-scale bioterrorist attack, in which anywhere between 500 and thousands of people would be exposed in a concentrated geographic region. Unfortunately, he says, this method would not have helped during the spate of anthrax outbreaks last fall.
What To Do: Learn more about the disease from the Centers for Disease Control and Prevention, MedlinePlus, or Johns Hopkins University's Center for Civilian Biodefense Strategies.
