Flu activity up in the United States, influenza A (H3N2) most common
Influenza activity continues to increase across most parts of the country, with nine out of 10 surveillance regions in the US seeing elevated activity, according to data from the Centers for Disease Control and Prevention (CDC) released Jan.4.
During the last week of 2012, the proportion of outpatient visits for influenza-like illness (ILI) was 5.6%; above the national baseline of 2.2%. Nine of 10 regions reported ILI above region-specific baseline levels. New York City and approximately 60 percent (29) of the states experienced high ILI activity. This is up from 16 states the previous week.
Between October 1, 2012 and December 29, 2012, 2,257 laboratory-confirmed influenza-associated hospitalizations were reported. This is a rate of 8.1 per 100,000 population. Among all hospitalizations, 1,924 (85.2%) were associated with influenza A and 312 (13.8%) with influenza B.
There were 18 pediatric deaths due to influenza during the last quarter of 2012.
Since the start of the season, influenza A (H3N2) viruses have predominated nationally, followed by influenza B viruses, while 2009 H1N1 viruses have been identified rarely.
The majority of currently circulating influenza viruses are susceptible to the neuraminidase inhibitor antiviral medications oseltamivir (Tamiflu) and zanamivir (Relenza). The CDC continues to recommend influenza vaccination and antiviral treatment when appropriate at this time.
Antiviral treatment, started as early as possible after becoming ill, is recommended for any patients with confirmed or suspected influenza who are hospitalized, seriously ill, or ill and at high risk of serious influenza-related complications, including young children, people 65 and older, people with certain underlying medical conditions and pregnant women.
Treatment should begin as soon as influenza is suspected, regardless of vaccination status or rapid test results and should not be delayed for confirmatory testing, according to the federal health agency.
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