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Influenza Season Overview: Health and Human Resources Subpanel Meeting, April 2012. David H. Trump, MD, MPH State Epidemiologist Director, Office of Epidemiology. Influenza Surveillance Refresher.
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Influenza Season Overview:Health and Human Resources Subpanel Meeting, April 2012 David H. Trump, MD, MPH State Epidemiologist Director, Office of Epidemiology
Influenza Surveillance Refresher • VDH Office of Epidemiology tracks the following key indicators to establish the statewide influenza activity level each week • Visits to emergency departments and urgent care centers for influenza-like illness (ILI) • ILI = fever with cough and/or sore throat • Laboratory test results confirming influenza • Outbreaks
2011-2012 Influenza Season • Late, short, and mild • Virginia and U.S. • Compared to past 15 flu seasons • Late – reached widespread level (affecting majority of regions of the state) week of February 25, 2012 • The latest time in the seasons studied • Short – stayed at widespread for only 3 weeks • Average of 9 weeks at widespread in 14 seasons (excluding May-December 2009 pandemic period) • Mild – highest percent of visits for ILI only 2%; only 4 confirmed outbreaks • Peak ILI 5% in 2010-2011; 33 outbreaks in 2011
Influenza Incidence Surveillance Project (IISP) – Other Viruses Cause ILI
Vaccine Composition for 2012-2013 • Composition has been identical for past two seasons • WHO and FDA recommend changes for next season’s vaccine • A/California/7/2009-like (2009 H1N1) – same • A/Victoria/361/2011-like (H3N2) – change • B/Wisconsin/1/2010-like (B/Yamagata lineage) – change • Recommendation based on surveillance on circulating viruses, serological responses to 2011-2012 trivalent seasonal vaccines, and availability of candidate strains and reagents
WHO Surveillance for Influenza A/H5N1 (Avian flu) • 600 cases since 2003 (as of 4/5/2012) • 353 (58.8%) have died • 2012 • 22 cases, 13 deaths • Bangladesh, Cambodia, China, Egypt, Indonesia,Viet Nam • Cases associated with exposure to sick or dead poultry or to live bird markets • Spread to household or community contacts not being seen
Conclusion • Influenza continues to behave unpredictably • Relatively mild season in U.S. this year • Circulating viruses matched vaccine strains • WHO continues to actively monitor avian influenza • Surveillance, vaccine, and vigilance are necessary for influenza control