During week 2, WHO and NREVSS laboratories reported 2,016 specimens tested for influenza viruses and 238 (11.8%) were positive. Of these, 105 were influenza A (H3N2) viruses, 2 were influenza A(H1N1) viruses, 125 were influenza A viruses that were not subtyped, and 6 were influenza B viruses.
Since October 2, 2005, WHO and NREVSS laboratories have tested a total of 43,434 specimens for influenza viruses and 2,092 (4.8%) were positive. Among the 2,092 influenza viruses, 2,026 (96.8%) were influenza A viruses and 66 (3.2%) were influenza B viruses. One thousand eighty-two (53.4%) of the 2,026 influenza A viruses have been subtyped: 1,075 (99.4%) were influenza A (H3N2) viruses and 7 (0.6%) were influenza A (H1N1) viruses. Forty-six states from all surveillance regions** have reported laboratory-confirmed influenza this season. Seven hundred fifty-four (36.0%) of the 2,092 isolates have been reported by the Mountain region and 479 (22.9%) have been reported by the Pacific region.
Based on this information and the trends in the linked report, we can expect influenza to reach the “epidemic” level in the next several weeks. The illness does this every year. There’s no reason to panic. The A)H3N2 variant is the one in the flu shot for this year and should provide a great deal of protection. No vaccine is 100% effective, so hand washing, staying away from infected people and healthy habits remain important.