The H1N1 flu virus could cause as many as 30,000 and 90,000 deaths in the United States and "poses a serious health threat" the Obama administration's advisory group on Science and Technology said in a report released Monday. Deaths would be concentrated among children and young adults, according to the report. In contrast, the typical seasonal flu kills between 30,000 and 40,000 annually — mainly among people over 65.

The report predicts 1.8 million will be hospitalized during the epidemic, with up to 300,000 patients requiring intensive care units.

These patients could occupy 50-100 percent of all ICU beds in affected regions at the peak of the epidemic and would place "enormous stress" on ICU units.

More needs to be done to speed up the "preparation of flu vaccine for distribution to high-risk individuals," otherwise the vaccine campaign – currently scheduled to begin in mid October — will have potentially missed the peak of the epidemic, according to the report.

"Based on the history of influenza pandemics over the past hundred years, PCAST places the current outbreak somewhere between the two extremes that have informed public opinion about influenza," states the report. "On the one hand, the 2009-H1N1 virus does not thus far seem to show the virulence associated with the devastating pandemic of 1918-19. On the other hand, the 2009-H1N1 virus is a serious threat to our nation and the world."