This flu season is already shaping up to be worse than the last.
Because flu season occurs in different time periods around the world, health experts track outbreaks of the virus globally to try and predict how the illness will affect each country before anyone there actually gets sick.
Predicting how bad a particular flu season will be is a tough call. But in many years, flu outbreaks in the southern hemisphere can help foretell the virus’ severity in the US. A group of scientists organised by the WHO called the Global Influenza Surveillance and Response System (GISRS) tracks the virus as it breaks out across the globe. By sharing their findings with one another, they try to predict which types, or strains, of the virus will cause the most sickness in the coming season. The scientists meet twice each year — once to assess the flu season for the Southern Hemisphere and once to predict its extent in the Northern Hemisphere.
In Australia, where flu season is the opposite of in the US (for Australians, flu season begins in May and ends in October), twice as many cases of the virus were reported this year than last. That means this flu season in the US — October to May — could be a doozy.
This chart, from a team of healthcare services analysts at the Royal Bank of Canada, shows how US flu outbreaks since 2009 have pretty accurately tracked the Australian viral outbreaks that immediately preceded them.
Last season, Australia reached a peak of just over 170 cases of the flu. This year, however, the country reported more than 350 cases.
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