ATLANTA — Up to 90,000 deaths from swine flu in the United States, mostly among children and young people?
Up to 1.8 million people hospitalized, with 50 percent to 100 percent of the intensive-care beds in some cities filled with swine flu patients?
Up to half the population infected by this winter?
On Monday, a White House advisory panel issued a report with these estimates, calling them "a plausible scenario" for a second wave of infections by the new H1N1 flu. The grim numbers by the panel, the President's Council of Advisers on Science and Technology, got considerable play in the news media.
Tuesday, however, officials at the U.S. Centers for Disease Control and Prevention, the agency with the most expertise on influenza pandemics, suggested that the projections should be regarded with caution.
A press officer for the CDC, speaking carefully to avoid a feud with the White House press office, said, "Look, if the virus keeps behaving the way it is now, I don't think anyone here expects anything like 90,000 deaths."
Even one of the experts who helped prepare the report said Tuesday that the numbers were probably on the high side, given that some weeks had passed since the calculations were finished in early August.
"As more data has come out of the Southern Hemisphere, where it seems to be fading, it looks as if it's going to be somewhat milder," said the expert, Marc Lipsitch, an epidemiologist at the Harvard School of Public Health. "If we were betting on the most likely number, I'd say it's not 90,000 deaths; it's lower."
For a report with such striking figures, it was released with little fanfare and less coordination than might have been expected among public health officials.
The report was posted on the White House Web site on Monday, two weeks late, since it was dated Aug. 7. With President Barack Obama on vacation in Martha's Vineyard, no press conference with the White House or with the report's authors was scheduled.
Kathleen Sebelius, the secretary of health and human services, was at the CDC headquarters in Atlanta, addressing a special symposium on swine flu.
A summary of the report was handed out by the CDC press staff to medical reporters as she spoke, but Sebelius did not dwell on it or mention its forecast of 30,000 to 90,000 deaths, more than twice the 36,000 deaths usually caused by seasonal flu.