Tracking Seasonal Flu
Knowing when and where influenza peaks will prepare public health workers to combat the disease
Seasonal flu outbreaks in older adults tend to move in waves, peaking earliest in western states such as Nevada, Utah and California and working their way east, according to a new Tufts study. Knowing that may help health-care providers better prepare for flu outbreaks.
“Because the peak of seasonal flu runs its course nationwide in a matter of weeks, it is often too late to adjust resources, including vaccinations and antivirals, once the first outbreak hits,” says Elena Naumova, professor of public health and community medicine at the School of Medicine. “We have identified patterns in seasonal flu and developed a model that allows us to better predict outbreak peak timing. This research will enable public health officials and hospitals to better prepare for seasonal flu, and work to reduce the number of patients experiencing more serious complications of the flu.”
The researchers also found that flu seasons that peaked early tended to be more intense, with more cases of the flu in those years.
Despite the geographic distance between Nevada, the earliest peaking state, and Maine, the latest one, Tufts researchers’ analysis of 13 flu seasons showed that the flu peaked in every state within a four-week span. Nationwide, the average flu season peak occurred during the third week of January.
“We found that of the 9.7 million hospitalizations in the elderly that occurred annually, 1.03 million, or 10.5 percent, were due to pneumonia and influenza,” says Naumova, who also directs the Tufts University Initiative for the Forecasting and Modeling of Infectious Diseases. “Adults over the age of 65 have the highest rates of complications or death as a result of the flu,” she says, “and studying the patterns of influenza in this population will help us better predict when and where an especially intense season will occur.”
For the study, which was published April 15 in the journal PloS One, Naumova and Julia Wenger, MPH09, analyzed hospitalization records from the Centers for Medicare and Medicaid Services from 1991 to 2004 and identified more than 248,000 hospitalization records relating to flu. The researchers used dynamic mapping as one of the tools to visualize data from each of the 48 states and Washington, D.C., for each of the 13 influenza seasons.