U.S. Surveillance Update Anthony Fiore, MD, MPH CAPT, USPHS Influenza Division National Center for Immunizations and Re

1. U.S. Surveillance Update Anthony Fiore, MD, MPH CAPT, USPHS Influenza Division National Center for Immunizations and Respiratory Disease Centers for Disease Control and Prevention Vaccines and Related Biological Products Advisory Committee Meeting Washington DC February 22, 2010

2. National Influenza Surveillance System State and Territorial Epidemiologists Population-based Hospitalization Pediatric Mortality Vital Statistics Registrars Sentinel Providers CDC Novel influenza A Laboratories Health Departments Public Health Officials Public Physicians Media Weekly FluView available at: http://www.cdc.gov/flu/weekly/fluactivity.htm

3. Influenza Surveillance Outpatient Illness Geographic Spread Hospitalizations Mortality Virus Monitoring Antiviral Resistance

4. Percentage of Visits for Influenza-like Illness (ILI) Reported by the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet), Weekly National Summary, October 1, 2006 – February 6, 2010

5. Influenza Surveillance Outpatient Illness Geographic Spread Hospitalizations Mortality Virus Monitoring Antiviral Resistance

13. Influenza Surveillance Outpatient Illness Geographic Spread Hospitalizations Mortality Virus Monitoring Antiviral Resistance

14. Cumulative rate of hospitalization/10,000 populationfor five age groups and three seasons, Emerging Infections Program, 2007-2009 * Pan H1N1 is for data from Sep 1, 2009 to Jan 21, 2010

15. Influenza Surveillance Outpatient Illness Geographic Spread Hospitalizations Mortality Virus Monitoring Antiviral Resistance

16. Pneumonia and Influenza Mortalityfor 122 U.S. CitiesWeek Ending 2/6/2010 EpidemicThreshold SeasonalBaseline 2005 2006 2007 2008 2009

17. Other Influenza Deaths Reported Current Week 2009 Influenza A (H1N1) Deaths Reported Current Week Other Influenza Deaths Reported Previous Weeks 2009 Influenza A (H1N1) Deaths Reported Previous Weeks Number of Influenza-Associated Pediatric Deaths by Week of Death:2006-07 season to present 2009-10 Number of Deaths Reported=260 2006-07 Number of Deaths Reported = 78 2007-08 Number of Deaths Reported = 88 2008-09 Number of Deaths Reported =132

18. Aggregate Hospitalizations and Deaths Reporting Activity (AHDRA) • Web-based influenza surveillance system implemented in response to the 2009 H1N1 pandemic • Collects reports of influenza-related hospitalizations and deaths from U.S. states and territories. • Approximately 44 jurisdictions report to AHDRA on average each week. • Reports include • Laboratory-confirmed case definition • Syndromic case definition - patients whose hospitalization or death is clinically identified as being associated with influenza-like illness (ILI) or pneumonia syndrome 

19. Weekly Laboratory-Confirmed Influenza-Associated Hospitalizations and Deaths Reported to AHDRA, National Summary, August 30, 2009 – February 6, 2010

20. CDC Estimates of 2009 H1N1 Influenza Cases, Hospitalizations and Deaths: Methods • Use data on influenza-associated hospitalizations from EIP • Correct for under-reporting and extrapolate to entire US population • Use AHDRA data to estimate number of deaths for estimated of hospitalizations • Cases estimated from EIP hospitalizations data using multipliers derived from a model developed in 2009* *Reed et al. Emerging Infectious Disease 2009

21. CDC Estimates of 2009 H1N1 Influenza Cases, Hospitalizations and Deaths: ResultsApril 2009 through January 16, 2010 http://www.cdc.gov/h1n1flu/estimates_2009_h1n1.htm

22. 2009 H1N1 Cases

23. 2009 H1N1 Hospitalizations

24. 2009 H1N1 Deaths

26. Summary of key epidemiologic findings: 2009 pandemic influenza A(H1N1) studies • Highest incidence of lab confirmed infections in school age children • Distribution of hospitalizations and deaths different from seasonal influenza • Highest hospitalization rates among 0 through 4 year olds • Hospitalization rates for Apr-Oct 2009 exceed cumulative rates for seasonal influenza among school age children and 19 through 49 year old adults • Relatively few severe cases among adults >65 years old • 50-70% of deaths and hospitalizations among persons with an underlying medical condition that confers higher risk for complications • Pregnancy is a higher risk condition • Newly recognized risk conditions? • Morbid obesity (BMI>40) –?proxy for unrecognized medical condition • Indigenous populations –?proxy for chronic medical conditions, poverty or medical care access • Neuromuscular diseases – even worse than usual?

27. Vaccine Effectiveness Studies • Challenges • Little seasonal influenza activity to assess effectiveness of 2009-10 seasonal vaccine • Peak 2009 H1N1 pandemic influenza activity preceded widespread 2009 H1N1 monovalent vaccine availability • VE studies underway • Prevention influenza-associated health care visits (mostly outpatient) in 4 sites enrolling prospectively: Flu VE Network • Marshfield, Michigan, Rochester, Vanderbilt • Prevention of influenza hospitalizations as diagnosed by provider-ordered tests in 10 Emerging Infections Program (EIP) sites • Assessments in Maine school systems • VE studies about to begin: • Pregnant women • Seriously ill children • Health care workers

28. Advisory Committee on Immunization Practices, February 22, 2010Influenza session • Update on season and pandemic • Vote on annual recommendations for use of seasonal vaccine • Adults • Children • Updated influenza vaccine strains