H1N1 Influenza A

1. H1N1 Influenza A Julie Casani, MD, MPH Public Health Preparedness and Response

2. How Flu Spreads • Most spread through coughing and sneezing • Contact transmission also important • Hand to hand, contaminated surfaces • Airborne transmission also possible

3. Influenza Survival on the Environmental Surfaces • Hard surfaces: 12–48 hours • Cloth/paper: 8–12 hours • Hands: 5 minutes • Survives longer with low humidity, low UV Weber & Stilianakis, Journal of Infection 57(5): 361-73

4. Novel Influenza Virus Infection • Human infection with influenza A virus subtype different from the circulating human subtypes

5. Pandemic Influenza • Three Conditions: • Novel virus (all or most susceptible) • Transmissible from person to person • Wide geographic spread

6. Impact of Past Influenza Pandemics

7. Summary of Events • March 28–30, 2009: 2 children from California seen for influenza-like illness • Same influenza A (H1N1) virus; not previously recognized among swine or human • April 26, 2009: US Government declares Public Health Emergency • June 11, 2009: WHO declares pandemic • Infections occurring around the world

8. What’s in a Name? • Swine flu • Swine-origin influenza virus (S-OIV) • Mexican flu • American flu • H1N1 • Novel H1N1 • 2009 H1N1 • Pandemic H1N1 • Others?

9. Where We Are Now • WHO Phase 6 Pandemic • Determined by global spread, not severity • Above normal flu activity across NC • “Second wave” in Fall • Likely mixed season with many strains circulating • Monitoring for increased transmissibility, increased virulence

10. Pandemic H1N1: Clinical Features • Most cases uncomplicated, typical influenza-like illness (ILI) • Diarrhea and vomiting might be more prominent than with seasonal flu • As of late July, 2009: • 12% reported US cases hospitalized* • 0.7% reported US cases died* * Skewed by testing of more severe cass

11. Hospitalizations • Detailed clinical data presented on >200 hospitalized patients (CDC) • 43 (21%) admitted ICU • 17 (8%) died • Median time from onset of illness to hospital admission • 3 days (range 1-14 days) • Median length of stay • 3 days (range 1-53)

12. Novel H1N1 Case Counts

13. Confirmed NC Cases by County of ResidenceAugust 12, 2009 Alleghany Gates Vance Currituck Rockingham Northampton Surry Camden Caswell Ashe Granville Stokes Warren Person Hertford Pasquotank Halifax Watauga Perquimans Wilkes Alamance Yadkin Forsyth Chowan Avery Mitchell Franklin Bertie Guilford Orange Nash Davie Caldwell Durham Alexander Yancey Edgecombe Tyrrell Madison Davidson Iredell Wake Martin Washington Dare Burke Randolph Chatham Wilson Catawba Rowan Pitt McDowell Buncombe Beaufort Greene Swain Haywood Johnston Hyde Lincoln Lee Rutherford Cabarrus Montgomery Graham Henderson Harnett Wayne Gaston Jackson Polk Moore Cleveland Stanly Lenoir Craven Mecklenburg Cherokee Macon Transylvania Pamlico Cumberland Clay Sampson Hoke Jones Anson Richmond Duplin Union Onslow Scotland Carteret Robeson Bladen Pender Columbus New Hanover Brunswick Confirmed Cases, N=687 (75 counties)

14. Influenza Surveillance Relies on: • Surveillance for influenza-like illness (ILI) • Sentinel Provider Network • Electronic syndromic surveillance • Systematic laboratory testing • Morbidity and mortality monitoring

15. Pandemic H1N1 Testing in NC • Testing at State Laboratory of Public Health • Hospitalized patients with ILI • Patients with ILI seen by sentinel providers • Algorithm for clinicians at www.flu.nc.gov • Testing also performed at some commercial and hospital-based laboratories

16. Rapid Flu Tests and Novel H1N1 • Sensitivity ranges 10–70% for novel H1N1 • Low negative predictive value • If negative, cannot be used to rule out novel H1N1 infection • High specificity • Good positive predictive value only if novel H1N1 prevalent in the community

17. Pandemic Flu Testing: Take Home • Treatment and control measure decisions should be based on clinical and epidemiologic information; not on testing

18. Pandemic Mitigation Strategies • Vaccination • Targeted antiviral treatment and prophylaxis • Nonpharmaceutical interventions • Hand hygiene, respiratory etiquette • Isolation and quarantine • Social distancing (school dismissal, cancellation of large gatherings, teleworking, etc.)

19. Pandemic Mitigation Strategies • Mitigation strategies guided by severity of illness

20. Pandemic H1N1 Vaccine • Monovalent vaccine • Separate from seasonal vaccine • Likely two doses, 3–4 weeks apart • Five manufacturers • Live attenuated vaccine available (~15%) • Clinical trials in progress, evaluating • Safety / adverse events • Interval between doses • Administration with seasonal vaccine

21. Pandemic Vaccine Availability* • Considering “early roll out” of some doses in late September • First large bolus expected mid-October • Near-Weekly shipments • Total amount dependent on uptake *Planning assumptions

22. Pandemic Vaccine Distribution • Vaccinators: • providers who agree to provide vaccine • Local Health Departments • Hospitals (for health care workers) • Vaccine costs: • Vaccine free • Administration fees

23. Pandemic Vaccine: Priority Groups • Pregnant women • People who live with or care for children younger than 6 months of age • Health care and emergency services workers • Persons 6 months through 24 years of age • People 25 through 64 years of age at high risk for complications of influenza

24. High Risk for Complications • Chronic pulmonary, cardiovascular, renal, hepatic, hematologic, neurologic, neuromuscular, or metabolic disorders • Immunosuppression • Persons younger than 19 years of age who are receiving long-term aspirin therapy • Residents of nursing homes and other chronic-care facilities

25. Seasonal Influenza Vaccine • Available now! • Should not delay • Recommended for • Children 6 months – 18 years • Adults ≥50 years • Pregnant women • Health care workers • Persons with certain medical conditions • Household contacts of children <5, adults >50, persons with certain medical conditions

26. Community Mitigation • Recommendations based on disease severity • Guidance issued for specific settings • Schools • Camps • Workplace • Health care facilities • Long-term care facilities • www.flu.nc.gov and www.cdc.gov/h1n1flu

27. School Guidance: “Similar Severity” • Stay home when sick • At least 24 hours after fever resolves without use of fever-reducing medicines • Separate ill students/staff • Emphasize hand hygiene • Routine environmental cleaning • Early treatment of high-risk students and staff • Consider of selective dismissal of schools with predominantly high-risk students

28. Health Care Settings: NC Recommendations* • Standard precautions • Gown, gloves, mask, eye protection as warranted • Droplet precautions • Surgical mask • Private room or cohorting • Strict hand hygiene and respiratory etiquette • Restriction of ill healthcare workers & visitors • Airborne precautions for aerosol-generating procedures *Consistent with SHEA/APIC/IDSA recommendations

29. Specific Sector Planning • Dept of Corrections • EMS • Law Enforcement-Judicial TTX

30. What some locales are doing • Seasonal flu vaccine messages as “hold” messages • Planning for absentees • Coordination for homebound people • Scrolling marquees on gov’t TV panels • Alamance Reads project

32. Resources • www.flu.nc.gov • www.cdc.gov/h1n1flu • www.pandemicflu.gov

33. Questions?