H1N1 incidence rate climbs, CDC notes peak as 'extremely unusual'

ATLANTA The H1N1 influenza pandemic of 2009 continued to surge last week, as the number of states reporting widespread activity climbed to 46, barely a few weeks into the official 2009-2010 cold-and-flu season, according to a Centers for Disease Control and Prevention briefing held Friday.

The CDC update was soon followed by a national emergency declaration from the White House.

Tom Frieden, CDC director, suggested that in a typical season, 46 states reporting widespread activity would represent the peak of illness in the season. That’s not necessarily the case this year.

“To be basically in the peak of flu season in October is extremely unusual,” Frieden said. ”It is though a very different pattern and the fact that we’re having a young person’s flu now doesn’t mean we’re not going to have an older person’s flu later in the year.”

And while more people are suffering from flu-like symptoms, fewer people have been able to get the flu shot be it either seasonal or H1N1. The H1N1 vaccine has been trickling out to states even as most flu clinics have exhausted their supplies of seasonal vaccine because of record demand. Already, many companies that provide flu clinic services, including Maxim Health, have had to cancel clinic offerings due to lack of seasonal vaccine.

To date, more than 85 million doses of seasonal vaccine have been distributed, with an additional 30 million on its way. “[News of seasonal vaccine shortages] were surprising to us until we got back, this week, new data about the uptake of seasonal flu vaccination— which has been unprecedented,” Frieden said. “By our estimates, over 60 million people have been vaccinated already for seasonal influenza,” he added, noting that this many inoculations delivered this early in a season is unprecedented.

“At the government [level] we are doing everything we can to get [the H1N1] vaccine out as soon as it becomes available,” Frieden said. “Shipping is overnight. We’re distributing to literally tens of thousands of doctors, hospitals, health centers throughout the country,” he said, suggesting there now is a significant amount of H1N1 vaccine available. As of Friday, there were 16.1 million doses available for shipping.

But that “significant amount” is proving to be not enough, Frieden conceded.

“What we have learned more in the last couple of weeks is that not only is the virus unpredictable, but vaccine production is much less predictable than we wish. We are nowhere near where we thought we’d be by now. We are not near where the vaccine manufacturers predicted we would be,” he said. ”The technology we are using, although it’s tried and true, is not well suited for pandemics.”

The number of H1N1 cases to date already number in the millions, Frieden said, and is disproportionately impacting younger people as compared to the seasonal flu. “This remains largely a young person’s disease, but we are seeing it increasingly affect young adults as well as children,” he said. “We are still not seeing significant numbers of cases in the elderly, and that is a characteristic of this virus which has not changed since spring.”

The pandemic influenza  is currently in its second wave, Frieden added, with the first occurring in the spring.

So far, the mortality rate associated with H1N1 remains relatively mild, and the H1N1 virus remains susceptible to such antiviral medicines as Tamiflu.