FRIDAY, Dec. 11, 2009 (HealthDay News) -- Swine flu infection rates continue to drop, U.S. health officials said Friday, with only 14 states reporting widespread H1N1 activity, down from 25 states last week and 48 states at the height of the outbreak in October.
Virtually all of the influenza viruses identified so far continue to be H1N1 swine flu virus. And the H1N1 vaccine continues to be a good match for the virus, as do the antiviral drugs Tamiflu and Relenza, the U.S. Centers for Disease Control and Prevention reported on its Web site.
The states still reporting widespread H1N1 swine flu activity are: Alabama, Alaska, Arizona, California, Connecticut, Delaware, Kentucky, Maine, New Hampshire, New Jersey, New York, Rhode Island, Vermont, and Virginia, the CDC said.
On Thursday, CDC officials reported that the H1N1 swine flu has sickened nearly 50 million Americans, sent more than 200,000 people to the hospital and killed nearly 10,000 -- more than 8,000 of them children and young adults.
"About 15 percent of the entire country has been infected with H1N1 influenza. That means about one in six people," Dr. Thomas R. Frieden, director of the U.S. Centers for Disease Control and Prevention, said during an afternoon press conference.
"That still leaves most people not having been infected and still remaining susceptible to H1N1 influenza," he added.
The swine flu continues to hit children and young adults the hardest, Frieden said. Among those who have died since the virus first surfaced in April, an estimated 1,100 were children and 7,500 were young adults, he noted. This is the reverse of seasonal flu, which tends to strike hardest at people 65 and older.
"By November 14, many times more children and younger adults have been hospitalized or killed by H1N1 influenza than occurs during a usual flu season," he said.
The swine flu has also been particularly virulent among the Native American and Alaskan Native populations, Frieden said.
"The death rate is about four times higher for this group," he said. "This is most likely largely a reflection of environmental factors and underlying conditions -- like diabetes and asthma -- that are more common, and access to health care, rather than a genetic or racial/ethnic difference."
Frieden said that, as has been noted before, the rate of H1N1 flu infections has subsided in recent weeks, but it's impossible to predict what the winter and spring might bring. About half of the experts interviewed by the CDC think there will be many more cases, while the other half is taking the opposite view. "The truth is we don't know," he said.
Meanwhile, the supply of H1N1 vaccine continues to grow, Frieden said. There are now 85 million doses of vaccine available, up another 12 million doses from last week.
"This is a good window of opportunity to get vaccinated," he said. "We don't know what the future will hold in terms of H1N1 influenza."
The swine flu continues to produce mild infections in most people, with recovery taking about a week. But certain groups remain at risk for complications, including pregnant women, children and young adults, and people with chronic health problems, such as asthma, diabetes and heart disease.
Frieden also noted that cases of the regular, seasonal flu have begun to show up. Influenza B has already killed one child, he said.
So far this year, about as many people as last year have gotten a seasonal flu shot. With 109 million doses of seasonal flu vaccine available, most of the supply has been shipped. But, people are still experiencing shortages of this vaccine, Frieden said.
In related news, health officials in Vietnam said they have identified a cluster of swine flu cases resistant to the antiviral drug Tamiflu. The cases involved seven people who had traveled together on a long train ride in July. They did not know each other before the trip, and all recovered, according to a report in the Dec. 10 issue of the New England Journal of Medicine.
An estimated 100 cases of Tamiflu-resistant H1N1 flu have been reported worldwide.
For more on H1N1 swine flu, visit the U.S. Health and Human Service Administration.