Swine Flu Virus Dominant Strain Worldwide: WHO

Nov. 6 -- THURSDAY, Nov. 5 (HealthDay News) -- The H1N1 swine flu virus is now the predominant flu strain worldwide, although it shows no signs of becoming more virulent and continues to produce mild-to-moderate symptoms in most people, the World Health Organization's flu chief said Thursday.

In some countries, the swine flu accounts for up to 70 percent of the flu viruses being sampled, Dr. Keiji Fukuda said during a press briefing, the Associated Press reported.

In the United States, virtually all flu activity right now is from the H1N1 virus, according to federal health officials.

But unlike seasonal flu, which typically strikes hardest at people over age 65, the H1N1 swine flu targets a disproportionate number of people under 65, Fukuda said.

"We remain quite concerned about the patterns that we're seeing," he said.

Fukuda said the H1N1 flu virus appears to be stable, with samples from around the globe very similar to those seen when the virus first emerged in Mexico and the United States in April, the AP said.

In the United States, a federal health official said Tuesday that the country had 31.8 million H1N1 flu vaccine doses available and was on track to have another 10 million ready by week's end.

So far, that hasn't been enough to prevent long lines at vaccination centers, but it is consistent with what officials had projected earlier this week.

"We're having a steady increase in the availability of vaccine, but not nearly as rapidly as we would have liked," Dr. Thomas Frieden, director of the U.S. Centers for Disease Control and Prevention, told reporters during a teleconference. "That is encouraging, but it is not nearly as much as we would like. We realize it is frustrating and inconvenient [to patients and to physicians]. As public health professionals, it is frustrating because, in part, many people who seek the vaccine will not get vaccinated later. They might not come back. We ask people to continue to be persistent."