A report published on December 13 in The Lancet has provided new estimates for the number of annual worldwide flu deaths. Based on a multinational survey conducted by the US-based Center for Disease Control (CDC) and global health partners, the report indicates that between 291,000 and 646,000 people worldwide die from flu-related respiratory illnesses each year - up from the previous estimate of 250,000 to 500,000.

The new estimates are based on data from a larger and more diverse pool of countries than previous estimates; 47 countries took part in the survey, providing regional and age-specific mortality estimates. The most vulnerable group was found to be Sub-Saharan Africans over 75 years of age. Flu mortality estimates from the Eastern Mediterranean and Southeast Asia were lower but still rather high compared to other regions.

"This work adds to a growing global understanding of the burden of influenza and populations at highest risk," said CDC researcher Danielle Iuliano, lead author of the study. "It builds the evidence base for influenza vaccination programs in other countries."

Research is currently underway to estimate non-respiratory causes of flu-associated deaths. Read more here and access the full report here (payment required).