MONDAY, Oct. 26 (HealthDay News) -- Because of production delays, far fewer than the goal of 40 million doses of H1N1 influenza vaccine will be available in the United States by the end of October, according to the U.S. Centers for Disease Control and Prevention. In addition, the U.S. Food and Drug Administration has issued an emergency use authorization for the investigational antiviral drug peramivir intravenous in certain patients with suspected or confirmed H1N1 infection.

The vaccine is growing more slowly in egg-based cultures than its manufacturers expected, which has resulted in the production delays, CDC director, Thomas R. Frieden, M.D., announced Oct. 23. Manufacturers had anticipated 40 million doses being available by the end of October, but they will fall far short of that number, Frieden said. As of Oct. 23, 16.1 million doses were available, up from 14.1 million on Oct. 21.

Also on Oct. 23, the FDA announced that, after a request from the CDC, it had issued an emergency use authorization for peramivir intravenous. The agency authorized the drug specifically for use in hospitalized adults and children with confirmed or suspected H1N1 for whom intravenous therapy is clinically appropriate for one or more reasons.

"We are now in the second wave of pandemic influenza, and whether this will continue through the fall into the winter, whether it will go away and come back in the traditional flu season, which peaks usually in December, January, February, only time will tell," Frieden said.

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