CDC has revised the death toll for the H1N1 pandemic to almost 10,000 people since April, a significant jump from mortality numbers released last month. A month ago, the CDC estimated that only about 4,000 had died. CDC also noted that:

  • 50 million Americans, one sixth of the country, had caught the disease
  • 213,000 people had been sick enough to be hospitalized

Several flu experts said they were not shocked by the sudden jump because the new figures were as of Nov. 14, when this fall’s wave of swine flu cases was reaching its peak. The previous estimate of 4,000 deaths, issued last month, was only through mid-October. By next month, deaths should not have risen quite as abruptly because the fall wave is tapering off and hospitals have fewer people in intensive care, experts said. “I’m not surprised,” said Lone Simonsen, an epidemiologist at George Washington University’s School of Public Health. “This includes most of the fall wave.”

How many will ultimately die of the H1N1 flu depends heavily on whether there is a third wave in January, as happened in the 1918 and 1957 pandemics, and on whether the virus changes to be more lethal or drug-resistant. Predicting that requires a crystal ball.

Dr. Thomas R. Frieden, Director of the CDC said about 85 million doses of the H1N1 vaccine were now available. Some states have so much that they are asking that everyone over six months old get vaccinated, not just high-risk individuals. There is “still a good window of opportunity” to get vaccinated, Dr. Frieden said, adding that he plans to get the nasal spray vaccine himself “in a few days.”

Mutations making the flu more lethal and drug-resistant have been spotted in many countries, but thus far only in small numbers of isolated cases.

Michael T. Osterholm, director of the CIDRAPat the University of Minnesota, agreed that trying to guess how many would die by spring was “calling the score at halftime.” Mr. Osterholm was troubled by recent predictions that the pandemic would be the mildest on record.

“So the C.D.C. says 50 million have been infected so far,” he said. “Another 50 million have been vaccinated. And maybe 20 million have got innate immunity because of their age. You do the math — that’s 120 million who are immune out of 320 million, so two-thirds of the population is still not immune. It’s amazing how many people are acting as if this is all wrapped up. The numbers could still go up dramatically.”

Dr. Arnold S. Monto, a flu expert at the University of Michigan School of Public Health, said the flu might reach the lower end of a widely publicized forecast made in August by the President’s Council of Advisers on Science and Technology, which predicted 30,000 to 90,000 deaths.

Deaths appear to be lower than expected, Dr. Monto said, partly because young victims are better able to tolerate the aggressive drug and oxygen therapy used in hospitals to save those with overwhelming pneumonia. Flu deaths are hard to count because tests are inaccurate and some people die without being tested. In addition, some die of heart attacks, emphysema or organ failure, though flu triggered their illness. About 36,000 die in a typical flu season, according to a well-known 2003 study, but epidemiologists used different methods to calculate the 10,000 swine flu deaths, said Dr. Beth P. Bell, of the CDC.

In 2003, they counted winter deaths over a decade; this season’s model is based on lab-confirmed flu hospitalizations. The old method would probably conclude that more than 10,000 had died thus far, but it is impossible to know how many, Dr. Bell said. Dr. Frieden said Thursday that all the experts he consulted were divided over whether the country would have a January wave. “Half think we will,” he said, “and half think we won’t.

Also, Dr. Frieden noted that American Indians and Eskimos had died at four times the rate of other Americans. That is probably not because of genetic differences, he said, but because of poverty and childhood malnutrition, among other factors. (Canadian Indians have also had high death rates. But so did Australian aborigines, who have similar rates of poverty, isolation and underlying disease but are genetically distant from North American Indians.)

http://www.cdc.gov/media/transcripts/2009/t091210.htm

http://www.nytimes.com/2009/12/11/health/11flu.html?em