"In these patients, the virus directly infects the lung, causing severe respiratory failure. Saving these lives depends on highly specialized and demanding care in intensive care units, usually with long and costly stays," said WHO.
In an update, WHO revealed that 15 per cent of the hospitals all across the globe reported that the patients hospitalized with the new H1N1 virus are needing intensive care.
"During the winter season in the southern hemisphere, several countries have viewed the need for intensive care as the greatest burden on health services," it said.
Minority group, indigenous populations and obese people seem to run higher risk with H1N1.
WHO estimates that more than 230 million people globally have asthma, and more than 220 million have diabetes.
However, AIDS victims are not at special risk from H1N1, WHO said.