New CDC estimates show what toll swine flu is taking in U.S.

By David Brown
Washington Post Staff Writer
Friday, November 13, 2009

About 22 million Americans have become ill with pandemic H1N1 influenza in the past six months and 3,900 have died, according to new estimates by the Centers for Disease Control and Prevention.

The number of pediatric deaths -- about 540 -- is four times as high as the number that physicians, hospitals and health departments had reported to the public health agency in Atlanta.

The new estimates, drawn from detailed surveillance and record-checking in 10 states, sketch the most detailed picture by far of the national toll from the new flu strain that emerged in California and Mexico in April.

"We feel we're finally able to update the public on how big a toll this virus is having so far," Anne Schuchat, a CDC physician helping to run the federal government's pandemic response, said Thursday. "I am expecting all these numbers, unfortunately, to continue to rise."

The total number of people who have been hospitalized is 98,000, with 36,000 of them age 17 and younger. The vast majority of deaths -- about 2,920 -- have been in people age 18 to 64.

In an average flu season, the seasonal virus contributes to the deaths of about 36,000 people -- 90 percent of whom are 65 or older. Many are close to death, with flu being only one factor leading to their demise. That is not the case with H1N1's victims, most of whom are much younger, and about 20 to 30 percent of whom were healthy before contracting the virus.

All of the estimates come with substantial uncertainty. For example, total H1N1 cases in the United States range from 14 million to 34 million, and total deaths from 2,500 to 6,100.

The CDC had previously said 129 people younger than 18 had died from H1N1 flu. That is compared with 88 deaths from seasonal flu in 2007-08 and 78 deaths in 2006-07 -- the most recent two flu seasons before the H1N1 strain emerged.

The new estimate includes deaths that occurred outside hospitals, patients who tested negative for H1N1 but almost certainly had it, and other overlooked cases.

"We don't think anything has changed," Schuchat said. "We think our 540 number is a better estimate for the big picture." She added, however, that the numbers affirm CDC's advice that "vaccination is the best effort to protect one's self or family."

As of Thursday, about 42 million doses of pandemic vaccine had been delivered to the federal government, which is distributing it to states and cities.

In an unrelated development, the World Health Organization on Thursday urged more aggressive use of antiviral medicines against the pandemic, especially in low-income countries where physicians may have been using the drugs only in severely ill people.

"People in at-risk groups need to be treated with antivirals as soon as possible when they have flu symptoms," Nikki Shindo, a WHO physician, said Thursday in a news briefing for reporters. "This includes pregnant women, children under 2 years old, and people with underlying conditions such as respiratory problems." Specifically, practitioners should not wait for lab test results or a worsening of a patient's condition before prescribing oseltamivir (Tamiflu), which is the main drug used against the H1N1 strain.

Roche, the Swiss pharmaceutical company that makes Tamiflu, is on track to make 33 million treatment courses a month by the end of the year, David Reddy, a company executive, said Thursday. The company has given 5 million courses to WHO and is delivering another 5 million.

Reddy said that more than 100 countries have Tamiflu stockpiles. The company's drug-safety tracking system suggests that at least 80 percent of the drug made in the past seven months has not been used.

Roche is selling Tamiflu at reduced prices to 72 countries, including Ukraine and several Central Asian nations formerly part of the Soviet Union, where the epidemic has been intense.

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