Jan 8, 2009 (CIDRAP News) – Only one state, Alabama, still had widespread pandemic H1N1 influenza activity last week, down from four the week before, and most other flu indicators were down as well, the Centers for Disease Control and Prevention (CDC) said today.
Pandemic activity in the United States has declined steadily since it peaked with widespread cases in 48 states in late October. And seasonal flu viruses have not yet emerged in any numbers to replace the pandemic strain, the CDC reported.
Alabama was back in the "widespread activity" column after reporting regional activity the previous week. Before that, the state had reported widespread activity for several weeks in a row.
Twelve states had regional activity last week, and most of the rest had only local outbreaks or sporadic cases. One state, Nebraska, reported no flu.
Laboratory-confirmed H1N1 hospitalizations and deaths continued to decline last week, according to CDC graphs. The percentage of deaths attributed to flu and pneumonia dropped to 7.4%, just below the 7.5% epidemic threshold, after edging above it during Christmas week.
The proportion of outpatient medical visits attributed to flu was 2.4%, just above the national baseline of 2.3% but down from last week's 3.2%.
Four flu-related deaths in children were reported, the same as the previous week, the CDC said. A total of 248 pediatric deaths have been tied to the pandemic virus.
Out of 4,180 specimens tested for influenza last week, only 161 were positive. Four of these were type B viruses, and the rest were all type A. The labs subtyped 92 of the 157 type A viruses and found that all were the pandemic H1N1 strain.
The CDC report comes as health officials prepare to launch National Influenza Vaccination Week on Jan 10 to promote continued immunization against the pandemic virus. Yesterday the agency warned against complacency, noting that in the pandemic of 1957-58, the crisis appeared to be over by December, but a winter surge of flu- and pneumonia-related deaths followed.
CDC Flu View report