The virus known as H1N1, or Swine Flu, is now believed to have killed about ten times more than what was reported, according to findings from a new study.

The study was a collaboration of more than 60 researchers from 26 countries and found the respiratory virus killed as many as 203,000 worldwide, Business Standard reported. The new analysis has officially challenged the total death toll reported by the World Health Organization (WHO).

"This study confirms that the H1N1 virus killed many more people globally than originally believed," study lead author Lone Simonsen, from George Washington University, told Business Standard. "We also found that the mortality burden of this pandemic fell most heavily on younger people and those living in certain parts of the Americas."

The study, published in the journal PLOS Medicine, was funded by WHO and the researchers were given access to weekly mortality virology data and the mortality data from 21 countries. The WHO had previously reported 18,449 deaths, but that figure was long understood to be low because it only counted lab-confirmed H1N1 cases.

The new count has taken into account all those who died but did not get their virus verified by a lab. Deaths were most common when the virus got into the respiratory system and caused pneumonia. They used the WHO's information, along with the non-lab-confirmed cases, to estimate the new death toll from the 2009 pandemic.

"We knew all along that lab-confirmed deaths were just the tip of the iceberg," Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told USA Today.

He said previous death tolls have only taken numbers into account and now it is common to examine what kind of people are dying due to these viruses. With H1N1, 62 percent to 85 percent of deaths were in people younger than the age of 65, in direct opposition with typical flu-related deaths in a given year.

"It's not just about the total number of deaths, but who is dying," said Osterholm. "In the past, we've used deaths as an indicator of severity. But a death in an 82-year-old is very different than in an healthy 21-year-old female who happened to be pregnant."