Using techniques similar to those used in weather forecasting, an international team of researchers has developed the first computer model that can accurately predict the timing and intensity of influenza outbreaks in subtropical regions.
The researchers, from Columbia University in the US and the University of Hong Kong, tested their modelling system on historical flu data collected by clinics and laboratories in Hong Kong between 1988 and 2013. The plan was to see how well it would have fared at predicting weekly flu forecasts throughout the period.
It didn't disappoint. The researchers' system successfully forecasted peak timing and magnitude of 44 epidemics in the region caused by individual flu strains - including influenza A (H3N2), influenza B - and both the seasonal and pandemic (2009) outbreaks of influenza A (H1N1). The modelling retrospectively predicted the peak timing of outbreaks three weeks in advance, with accuracy as high as 93 percent.
Unlike more temperate environments such as the US, subtropical climates pose a greater challenge for health researchers and authorities. In temperate climates the flu is largely contained to winter, but in subtropical regions influenza outbreaks can occur throughout the year and may occur more than once. The development of computer modelling that can so accurately forecast when the disease will hit could literally prove to be a life-saver for health systems in subtropical regions.
"These forecasts provide information at lead times that can be valuable for both the public and health officials," said senior author, Jeffrey Shaman from Columbia University, in a statement to the press. "Individuals may choose to get a flu vaccine to protect themselves against infection, while officials can anticipate how many vaccines and other supplies are needed, as well as the number of clinicians and nurses needed."
With the retrospective testing of the system now concluded, the researchers intend to use the software in real-time analyses to publish predictions for Hong Kong ahead of the 2015 influenza season. Their modelling already actively forecasts in US cities.
The flu is estimated to kill between 250,000 and 500,000 people around the world each year, so the ability to predict and mitigate outbreaks in subtropical climates – from which dangerous strains often emanate – should make a considerable impact in how we fight the disease.
"Hong Kong is a crossroads to Asia and the rest of the world, serving as an entry and exit point for flu outbreaks year round," said Benjamin J. Cowling from the University of Hong Kong. "[A]nd the region of South East Asia with Hong Kong at its centre is often referred to as the global epicentre for flu."
The research has been published in PLOS Computational Biology.