Scientists have developed a system to predict the timing and severity of seasonal influenza outbreaks that could one day help health officials and the general public better prepare for them. The system adapts techniques used in modern weather prediction to turn real-time, Web-based estimates of influenza infection into local forecasts of seasonal flu.
Results appear online in the Proceedings of the National Academy of Sciences.
Year to year, and region to region, there is huge variability in the peak of flu season, which, in temperate areas of the Northern Hemisphere, can happen as early as October or as late as April. The forecast system can provide "a window into what can happen week to week as flu prevalence rises and falls," says Jeffrey Shaman, PhD, an assistant professor of Environmental Health Sciences at Columbia University's Mailman School of Public Health.
As a test case, Dr. Shaman and Alicia Karspeck, PhD, of the National Center for Atmospheric Research, used Web-based estimates of flu-related sickness from the 2003-2008 influenza seasons in New York City to retrospectively generate weekly flu forecasts and found that the technique could predict the peak timing of the outbreak more than seven weeks in advance of the actual peak.
In the future, such flu forecasts might conceivably be disseminated on the local television news along with the weather report, says Dr. Shaman. Like the weather, flu conditions vary from region to region; Atlanta might peak weeks ahead of Anchorage. "Because we are all familiar with weather broadcasts, when we hear that there is a 80% chance of rain, we all have an intuitive sense of whether or not we should carry an umbrella," says Dr. Shaman. "I expect we will develop a similar comfort level and confidence in flu forecasts and develop an intuition of what we should do to protect ourselves in response to different forecast outcomes."
As individuals, a flu forecast could prompt us to get a vaccine, exercise care around people sneezing and coughing, and better tune in to how we feel. For health officials, it could inform decisions on how many vaccines and antiviral drugs to stockpile, and in the case of a virulent outbreak, whether other measures, like closing schools, is necessary.