HOUSTON, Oct. 2 (Xinhua) -- The U.S. federal Centers for Disease Control and Prevention (CDC) on Friday reported that 443 people had died of influenza and pneumonia-associated complications in the past week, bringing the death toll to 1,379 since the beginning of September.
Meanwhile, according to the latest statistics released by the CDC, 6,092 people across the country have been admitted last week to hospitals resulting from all types or subtypes of influenza, not just those from the A/H1N1 influenza virus, bringing the total number to 16,174.
Last Friday, the CDC reported 572 influenza and pneumonia-related deaths and 10,082 hospitalizations for the previous week.
In an effort to add additional structure to the aggregate reporting, the Council of State and Territorial Epidemiologists (CSTE) and the CDC have developed new case definitions for influenza-associated hospitalizations and deaths to be applied for the 2009-2010 influenza season, formally beginning from Oct. 4.
This new system was implemented on August 30, 2009 and replaces the weekly report of laboratory confirmed A/H1N1-related hospitalizations and deaths since July. States can now report to the CDC either laboratory confirmed or pneumonia and influenza syndromic hospitalizations and deaths resulting from all types or subtypes of influenza.
To allow states to implement the new case definition, counts were reset to zero by the CDC on August 30, 2009.
The CDC said the latest data shows that 27 states had geographically widespread influenza activity in the past week, comparing to 26 states in the previous week. Eighteen states had regional influenza activity in the past week, nearly doubling the previous total of eleven.
These key figures indicate that, during the past week, influenza activity has remained elevated in the United States and the second wave of the pandemic of the A/H1N1 flu is imminent.
Any reports of widespread or regional-spread influenza activity in September are very unusual, the CDC explained in its latest weekly report.
The seasonal influenza A (H1) and A (H3) viruses co-circulated at low levels with the A/H1N1 virus, the CDC said in a conclusion, adding that 99 percent of all subtyped influenza A viruses being reported to the CDC last week were the new A/H1N1 virus.
However, the CDC said that, during the past week, all deaths reported through the 122-Cities Mortality Reporting System due to pneumonia and influenza (P&I) remained at 6.1 percent, still below the epidemic threshold of 6.4 percent.
Nationwide, 4.2 percent of patient visits -- comparing to 4.6 percent in the previous week -- has been reported through the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet) were due to influenza-like illness (ILI), according to the CDC experts, who point out to the fact that this percentage still almost doubles the national baseline of 2.4 percent.
"Visits to doctors for influenza-like illness (ILI) continued to increase in some areas of the country, and overall, are higher than levels expected for this time of the year," the CDC said.
The latest CDC statistics also show that the total influenza hospitalization rates for laboratory-confirmed influenza are much higher than expected for this time of year for adults and children.
The A/H1N1 virus infection was first identified in the United States in late April. By August, 555 people had died of the new virus with hospitalizations of 8,842. More than 40,000 confirmed and probable cases had been reported and more than one million infections were estimated to have occurred in the United States.
The CDC and state officials are preparing for massive A/H1N1 flu immunizations, starting with school children in the first week of October.
Fortunately, almost all of the influenza viruses identified so far are A/H1N1 influenza viruses, according to the CDC experts, who believe that "these viruses remain similar to the virus chosen for the 2009 A/H1N1 vaccine, and remain susceptible to the antiviral drugs oseltamivir and zanamivir with rare exception.
