22 Million Cases of Swine Flu in U.S.
Up to 6,100 Deaths -- and Counting -- as Flu Hits 'Historic Levels'
WebMD News Archive
Nov. 12, 2009 -- H1N1 swine flu has killed more
than 4,000 Americans -- perhaps as many as 6,000, the CDC now
Shockingly, 14 million to 34 million U.S. residents -- the CDC's best guess
is 22 million -- came down with H1N1 swine flu by Oct. 17, the six-month
anniversary of the beginning of the pandemic. There were about 98,000
hospitalizations (estimates range from 63,000 to 153,000).
In the four weeks since Oct. 17, H1N1 swine flu has been widespread across
the nation. That means the new estimates, which greatly increase previous
counts, will have risen sharply.
"We do think we are having a substantial number of deaths," CDC immunization
and respiratory disease chief Anne Schuchat, MD, said at a news conference.
"The numbers are only through Oct. 17, and we have seen a lot of deaths since
then. Unfortunately, we will see more. ... I do believe the pediatric death
toll will be extensive and much more than we have seen with seasonal flu."
How much the numbers have gone up will only be known when CDC
epidemiologists are able to update the figures, which the CDC will do "every
three or four weeks." However, it's becoming clear that a huge fraction of the
population will have become ill before the flu season ends.
CDC data from Aug. 30 to Oct. 31 show flu activity is "substantially above
historic levels in all U.S. surveillance systems," according to today's
Morbidity and Mortality Weekly Report.
Nationwide, the number of flu patients showing up in doctors' offices and
clinics was higher in September and October than at the peak of any flu season
since record keeping began in 1997.
"We have tracked influenza for years. What we are seeing in 2009 is
unprecedented," Schuchat said. "To have very high rates of flu in September and
October is extremely unusual. ... If we look back, we don't see a fall like
Previous CDC estimates of H1N1 swine flu cases have been based on
laboratory-confirmed infection. But not everyone who gets the flu is
hospitalized with the flu, and not everyone who dies of the flu was tested. And
the tests miss many people who actually do have flu.
To correct these underestimates, the CDC bases the new estimates on detailed
clinical information reported by the Emerging Infections Network, a
collaboration of 62 counties in 10 states, and on aggregate data reported from
all states. This data is the used to derive estimates for the entire U.S.
"This is not a switch or a change, just a bigger picture," Schuchat