Preparing for Swine-origin Influenza A (S-OIV or H1N1)

1. Preparing for Swine-originInfluenza A (S-OIV or H1N1) September 9, 2009

2. Origins/ Severity of Illness • An unexpected surge in influenza A cases toward the end of the 2008-9 flu season was noted around Mexico City in April, 2009, and shortly thereafter, in California & Texas. • Exposure to pigs is not a risk factor for infection. • Most cases are relatively mild and the case fatality rate in the U.S. of .05% is less than that of the typical seasonal flu.

3. Antigenic Drift/ Shift • Influenza viruses consist primarily of 3 viral types: A, B, & C • Types A & B cause most of the severe mortality and morbidity • Influenza A viruses mutate and result in the emergence of new variants of prevailing strains each year • These changes are typically the result of minor changes in surface antigens or proteins • New variants result in seasonal flu each winter and require updated vaccines

4. Resurgence of H1N1 • Swine-origin influenza A (H1N1), also known as the “swine flu”, appeared 1st in North America at the end of the 2008-2009 influenza season and began spreading internationally. A prior outbreak occurred in 1976. • Since its appearance in the U.S., over 1 million Americans are thought to have contracted H1N1 & about 500 have died (1 in 20,000). • Swine flu is more of a threat to children under 2, pregnant women, teens, young adults, adults with chronic heart, lung, kidney, or liver problems, diabetics, & immune compromised persons (i.e. HIV, those on chemotherapy), nursing home and long term care facility residents.

5. Novel H1N1 Vaccine • The CDC is currently working on a vaccine which is slated to be released between mid-October and December • Although shortages are not anticipated, if initially limited quantities only are available, the following groups are to be given priority: • 1) Pregnant women • 2) Children 6 mos.- 4 years of age • 3) People who live with or care for children<6 months of age • 4) Health care personnel with direct pt. contact • 5) Children 5-18 with chronic med. illnesses

6. Seasonal Flu • Flu shots for the seasonal flu should be given as early as possible, but they won’t protect against S-OIV- H1N1 • Treatment for suspected seasonal flu with tamiflu or relenza within 48 hours of presentation • Typical clinical findings: subjective fever, cough, sore throat, fatigue, headache, chills, muscle aches • Watch for superinfection with bacterial infection as evidenced by colored sputum or nasal discharge, higher fevers, symptoms of pneumonia

7. S-OIV- HINI Clinical Features • 60% of those infected to date are under 18 • Approximately 50% of patients with HIN1 have nausea, abdominal pain, & diarrhea, in addition to “typical” flu symptoms, the former of which are atypical for the seasonal flu • Incubation period estimated between 1-4 days • Complication rates felt to be similar to seaonal flu, i.e. sinusitis, otitis media, pneumonia, worsening of asthma, myositis, pericarditis, encephalitis, etc.

8. Who should be tested? • Priority testing for persons who: • 1) Require hospitalization • 2) Are at high risk for severe disease • Methods: nasopharyngeal swab or aspirate, nasal swab plus throat swab or nasal wash • Most physician’s offices will not be equipped for proper testing with the use of proper protective equipment & use of adequate technique to diminish false negative results • Typical symptoms will be treated empirically

9. Anti-virals • Inhibit viral release from Host Cell(neuraminidase inh.)- prevents viral propagation- not a cure; typically shortens the duration of the flu by about 1 day and decreases the severity of the disease • 1) Tamiflu (Oseltamivir)- given 75 mg BID x 5 days for treatment and 75 mg qd x 10 days for prophylaxis to close contacts with infected individuals; Potential side effects: GI upset, headache, bronchitis, insomnia, vertigo, fatigue, delirium, hallucinations • 2) Relenza (Zanamivir)- given 2 inhalations (10 mg) twice daily for 5 days for treatment & 10 mg once daily for 10 days within 36^ of exposure for prophylaxis; Pot. side effects: bronchospasm, anaphylaxis, nausea, dizziness, cough, delirium, • fevers, chills, myalgias

10. Preventive Measures • Maintain a distance of at least 1 meter from a person with a flu-like illness • Wear a mask while providing care for a person with an influenza-like illness • Avoid touching your eyes, nose, or mouth, especially when in a crowded place • Wash hands often either with soap and water or with an alcohol-based hand rub for 20-30 seconds • Open windows in our living space to improve airflow if possible

11. Advise for people with flu-like illness • Stay home for 7 days after onset of symptoms or 48 hrs. after symptoms resolve • Maintain a distance of 1 meter from all people • Cover your mouth and nose with tissues when coughing or sneezing, & dispose of tissues immediately after use • Avoid touching eyes, nose, mouth • Wash hands with soap & water or alcohol-based rub for 20-30 seconds, particularly after touching your eyes, nose, or mouth • Open windows in living area if possible • Wear a mask when in close contact with others

12. Global capacity for production seasonal influenza vaccine • Estimated global capacity of 400 million doses • Process of vaccine production takes 4-6 months & was begun last April • In 1976, the swine influenza immunization program was complicated by an unexpectedly high incidence of GuillaineBarre syndrome, resulting in a halt in vaccine production • Influenza viruses have not commonly been found to trigger Guillaine Barre syndrome, except during major outbreaks

13. Epidemic comparisons

14. Resistance • With widespread use of tamiflu (oseltamivir), resistance strains will certainly develop • Resistance also develops spontaneously • Adding a stockpile of a 2nd agent (i.e. relenza (zanamivir)) either sequentially or in combination with tamiflu can effectively prevent or at least delay the development of resistance

15. Complications • Secondary bacterial pneumonia is a possible complication to the influenza virus • Need to watch for the development of purulent sputum or nasal discharge, high fevers, prostration, pleuritic pain, hemoptysis, or worsening after initial improvement • Methicillin-resistant Staph aureus is an infrequent cause of pneumonia complicating the flu, but has high case fatality rate

16. Influenza vs. cold

17. Summary • The world is much better prepared for H1N1 than prior influenza epidemics • It is important to compare the current H1N1 to the seasonal flu and prior pandemic influenza to gain perspective on what to expect at this time • The low case fatality rate and predilection for children and young adults for severe cases should be of some assurance to otherwise healthy persons in their 30’s-60’s • The anticipated H1N1 vaccine should be available between October-December, but potential side effects of the new vaccine need to be considered, esp. in view of the 1976 experience with swine influenza mass immunization

18. QUESTIONS? • More Information: • www.cdc.gov/h1n1flu/ • Palm Beach County Health Dept.- • 561-840-4568

19. Presented by: • Robert Briskin, M.D., Fellow of the American College of Physicians • VIP Primary Care Associates, P.A. • 210 Jupiter Lakes Blvd., Ste. 3205 • Jupiter, Florida • 561-746-9404 • vipprimarycare@yahoo.com • www.vipprimarycare.com