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

National Influenza Surveillance System CD C Laboratories Sentinel Providers State and Territorial Epidemiologists Vital Statistics Registrars Public Health Officials Physicians Media Public Health Departments Population-based Hospitalization Pediatric Mortality Novel influenza A Weekly FluView available at:

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

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

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

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

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

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

Epidemic Threshold Seasonal Baseline Pneumonia and Influenza Mortality for 122 U.S. Cities Week Ending 2/6/

Number of Influenza-Associated Pediatric Deaths by Week of Death: season to present Number of Deaths Reported = Number of Deaths Reported = Number of Deaths Reported =132 Other Influenza Deaths Reported Current Week Other Influenza Deaths Reported Previous Weeks 2009 Influenza A (H1N1) Deaths Reported Current Week 2009 Influenza A (H1N1) Deaths Reported Previous Weeks Number of Deaths Reported=260

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

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

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

CDC Estimates of 2009 H1N1 Influenza Cases, Hospitalizations and Deaths: Results April 2009 through January 16,

2009 H1N1 Cases

2009 H1N1 Hospitalizations

2009 H1N1 Deaths

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?

Vaccine Effectiveness Studies Challenges –Little seasonal influenza activity to assess effectiveness of 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

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