Pandemic (H1N1) 2009 Epi- Surveillance Update (Updated October 7, 2009)
Highlights:
• Effective August 12, 2009, local health departments began reporting hospitalized pandemic (H1N1) 2009 cases as weekly aggregate numbers. From October 4 – October 10, 2009, 237 hospitalized/fatal cases were reported; there have been 3,051 hospitalizations and/or fatalities, with 688 cases requiring intensive care, reported to date.
• The statewide incidence rate of reported pandemic (H1N1) 2009 hospitalizations and fatalities is 7.3 per 100,000 population.
• CDPH received 13 reports of fatal pandemic (H1N1) 2009 cases this week as of October 10, 2009; a total of 219 pandemic (H1N1) 2009 deaths have been reported to CDPH to date.
• In recent weeks, almost all influenza A-positive specimens tested by PCR at VRDL and by the Respiratory Laboratory Network have been subsequently confirmed as pandemic (H1N1) 2009, reflecting that the predominant circulating influenza strain in California remains pandemic (H1N1) 2009.
• Surveillance for the detection of antiviral resistance in pandemic (H1N1) 2009 influenza is ongoing. To date, of 683 specimens tested at VRDL, all but one have tested negative for the resistance mutation. VRDL detected one specimen with the H275Y resistance mutation (associated with oseltamivir resistance); the result was confirmed by the CDC. VRDL and CDC are continuing prospective antiviral resistance testing from a sampling of pandemic (H1N1) 2009 influenza viruses through the summer and the 2009-10 influenza season.