2011...


Influenza is a highly contagious respiratory illness that is responsible for significant morbidity and mortality. Approximately 9% of the world’s population is affected annually, with up to 1 billion infections, 3 to 5 million severe cases, and 300,000 to 500,000 deaths each year

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3278149/#:~:text=Influenza%20is%20a%20highly%20contagious,to%20500%2C000%20deaths%20each%20year.

thats the National Institute of Health btw...