WASHINGTON -- Swine flu has sickened about 22 million Americans since April and killed nearly 4,000, including 540 children, according to startling federal estimates released Thursday.
The figures - roughly a quadrupling of previous death estimates - don't mean swine flu has suddenly worsened, and most cases still don't require a doctor's care. Instead, the numbers are a long-awaited better attempt to quantify the new flu's true toll.
Until now, the CDC has conservatively estimated more than 1,000 deaths and "many millions" of new H1N1 infections. Earlier figures were based on laboratory-confirmed cases even as doctors largely quit using flu tests months ago - and experts knew that deaths from things like the bacterial pneumonia that often follows flu were being missed.
