The proportion of deaths attributed to pneumonia and influenza (P&I) in the United States was again below the epidemic threshold during the week of Dec. 27, 2009-Jan.2, 2010, the federal Center for Disease Control and Prevention (CDC) said on Friday.

"During week 52 (ending on Jan. 2), 7.4 percent of all deaths reported through the 122-Cities Mortality Reporting System were due to P&I. This percentage was below the epidemic threshold of 7.5 percent for week 52," the CDC said on its website.

Since last October, when the A/H1N1 pandemic peaked and as many as 48 states had widespread activity of the new virus, the proportion of deaths attributed to P&I based on the 122 Cities Report had been above the epidemic threshold for 11 weeks running.

As A/H1N1 flu continues to wane, the proportion of deaths linked to P&I based on the 122 Cities Report was dipping below the epidemic threshold in week 50, but bouncing back in week 51.

The epidemic threshold is the point at which the observed proportion of deaths attributed to pneumonia or influenza is significantly higher than would be expected at that time of the year in the absence of substantial influenza-related mortality.

The latest statistics released by the CDC show that, from Aug. 30, 2009 to Jan. 2, 2010, there were 37,778 laboratory-confirmed influenza-associated hospitalizations and 1,735 laboratory-confirmed influenza-associated deaths, including 229 of young patients under age 18, that have been reported to the federal agency.

But health officials believe that the actual death toll has been much higher than the figures of laboratory-confirmed influenza-associated deaths.

CDC officials had estimated that A/H1N1 flu has sickened nearly50 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.

"The estimates are actually much more accurate than the confirmed numbers," CDC Director Dr. Thomas Frieden said. "The number of confirmed deaths is really just a small proportion of the number of total deaths," he explained.

On the whole, the CDC reported on Friday that the A/H1N1 flu infections continue to be on the wane nationally, saying that "most key indicators declined compared to the previous week."

The first wave of the A/H1N1 pandemic began in April, when the strain was discovered. A larger wave started in late summer. Though the second wave has peaked, health experts stressed that it"e;s too soon to say it"e;s over.

"The H1N1 virus is still circulating, and it"e;s still causing disease, hospitalizations and deaths," Anne Schuchat, head of the CDC"e;s National Center for Immunization and Respiratory Diseases, said on Thursday at a press conference.

"I am concerned that people may be complacent, that people may think this is all over. I would hate for people to make decisions thinking there is no risk and then get sick or severely ill," she explained.

With 136 million doses of the A/H1N1 flu vaccine now available, Dr. Schuchat advised Americans who have not yet been vaccinated to get the vaccine as soon as possible.

Source: Xinhua