The swine flu virus swept across the globe in 2009, claiming thousands of lives in 12 countries.
But the H1N1 pandemic may have been much more widespread than first reported.
According to a new study released Monday by The Lancet, researchers now estimate more than 284,000 people died the first year the virus spread.
That's 15 times higher than the initial World Health Organization tally for the first 16 months.
Researchers say the numbers were skewed in Africa and Southeast Asia.
Researchers blame the high mortality rate in Africa on a lack of access to health care and vaccines.