U.S. Influenza Surveillance Update, 2007-8 Season

1. U.S. Influenza Surveillance Update, 2007-8 Season Joseph Bresee MD Epidemiology and Prevention Branch, Influenza Division, CDC VRBPAC Meeting Feb 21, 2008 Gaithersburg, MD

2. Seasonal Influenza Geographic Spread Virus Monitoring Mortality Outpatient Illness Hospitalizations Antiviral Resistance

3. 21 states and the District of Columbia reported sporadic influenza activity • 26 states reported no influenza activity ▪ 3 states reported local activity

4. 33 states and the District of Columbia reported sporadic influenza activity • 13 states reported no influenza activity ▪ 4 states reported local activity

5. 33 states, The District of Columbia and Puerto Rico reported sporadic influenza activity • 3 states reported no influenza activity ▪ 9 states reported local activity • 5 states reported regional activity

6. 10 states and Puerto Rico reported sporadic influenza activity • 17 states and the District of Columbia reported local activity • 17 states reported regional activity ▪ 6 states reported widespread activity

7. 4 states and Puerto Rico reported sporadic influenza activity • 9 states and the District of Columbia reported local activity • 26 states reported regional activity ▪ 11 states reported widespread activity

8. 2 states and the District of Columbia reported local activity • 17 states reported regional activity ▪ 31 states reported widespread activity

9. 1 state and the District of Columbia reported local activity • Puerto Rico reported sporadic activity • 5 states reported regional activity ▪ 44 states reported widespread activity

10. Seasonal Influenza Geographic Spread Virus Monitoring Mortality Outpatient Illness Hospitalizations Antiviral Resistance

11. U.S. WHO/NREVSS Collaborating LaboratoriesNational Summary, 2007-08 Since Sept 30- 14%of109,089specimens tested positive for influenza viruses 83% A 17% B of 28% of A viruses subtyped: -37%A (H1) viruses -63%A (H3) viruses

12. U.S. WHO/NREVSS Collaborating LaboratoriesNational Summary, 2007-08 In most recent week- 34% of 6,889 specimens tested positive for influenza viruses 79% A 21% B of 23% of A viruses subtyped: -11% A (H1) viruses -89% A (H3) viruses

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

14. Pneumonia and Influenza Mortalityfor 122 U.S. CitiesWeek Ending 02/16/2008 EpidemicThreshold SeasonalBaseline 2008 2004 2005 2006 2007 40 50 10 20 30 40 50 10 20 30 40 50 10 20 30 40 50 10 20 30 40 50 10

15. Number of Influenza-Associated Pediatric Deaths by Week of Death: 2005-06 season to present

16. Seasonal Influenza Geographic Spread Virus Monitoring Mortality Outpatient Illness Hospitalizations Antiviral Resistance

17. Percentage of Visits for ILI & ARI Reportedby Sentinel Providers and BioSense Outpatient Facilities,National Summary

18. Seasonal Influenza Geographic Spread Virus Monitoring Mortality Outpatient Illness Hospitalizations Antiviral Resistance

19. EIP Influenza Laboratory-Confirmed Cumulative Hospitalization Rates for Children Aged 0-4 and 5-17 yrs, 2007-2008 and Previous 2 SeasonsSeptember 30 – February 2, 2008

20. Seasonal Influenza Geographic Spread Virus Monitoring Mortality Outpatient Illness Hospitalizations Antiviral Resistance

21. Oseltamivir resistance, 2007-8 Influenza Season, U.S. • 5.7% (27/471) of influenza isolates tested were oseltamivir-resistant • 27 (8.1%) of 312 H1N1 resistant (all with H274Y mutation) • 0 / 76 H3N2 • 0 / 83 B • All regions of the country • No travel history known for any case • No oseltamivir exposure known • Apparent typical clinical illness and severity • All H1N1 oseltamivir-resistant viruses tested susceptible to zanamivir and adamantanes • 31% (88/282) influenza A viruses tested resistant to adamantanes • 99% of H3N2 viruses and 7.2% of H1N1 viruses

22. A (H1N1) oseltamivir resistance – Europe, Canada, Asia(as of 14 February 2008) Global – 14% (237 / 1703) • Europe – 20% (202 / 987) • 13 of 22 countries with resistant H1s • Asia - 2.1% (7 / 319) • 2 of 7 countries (no resistance in Japan) • Africa – 0% (0 / 18) • Americas • Canada – 6% (8/128) • Latin America – 0% (0/9) WHO data

23. Oseltamivir resistance – Plans to address Enhanced Surveillance • Increased numbers of viruses for testing • Collect detailed clinical, epi data on each case • Standard reporting form that is sent to SHDs Communications • Talking points and Q&As developed and distributed • Share materials with international and national partners (e.g. WHO, ECDC, CSTE, APHL, ACIP) • Press briefings Policy • No change in policy for use of antivirals at this point • ACIP Influenza WG discussed antiviral policy

24. Interim Estimation of Influenza Vaccine Effectiveness During the 2007-08 Season CDC partnered to develop capacity to provide annual VE estimates • This season, will conduct studies to provide VE estimates during the season Methods • Population: People recommended by ACIP to receive annual vaccination • Outcome: Medically attended influenza diagnosed by RT-PCR • Exposure: Vaccination status confirmed by validated vaccine registry Status • From Jan 21 through Feb 8, 616 (69%) of 896 eligible patients were tested • 191 (31%) were PCR-positive for influenza; 144 (75%) of those had influenza A • Preliminary results indicates vaccine provides • Some protection against infections with influenza A viruses • No protection against infections with influenza B viruses Plans • Continue enrollment • Type/subtype data pending – for type/subtype-specific analyses • Report of data during the season

25. Draft ACIP Agenda: Influenza SessionFeb 27, 2008 • Influenza vaccine effectiveness among 6-23 month old children, 2005-6 and 2006-7 seasons • Influenza vaccine strain selections 2008-09 • Oseltamivir-resistant influenza A (H1N1) • Expanding influenza vaccination recommendations to include all 5-18 year old children • Influenza vaccination recommendations, 2008 • Vote • VFC Vote