2009 New York City Department of Health and Mental Hygiene
(NYC DOHMH) Health Alert #14: Swine Influenza Update
April 29, 2009


PLEASE NOTE: This is a rapidly evolving situation. This alert provides interim guidance. It is possible that evidence of community transmission of Swine-Origin Influenza A (H1N1) (S-OIV) will emerge in the next few days. If and when community transmission is established, and as more information is available, this guidance will change.

Refer to Health Alert # 13 for current reporting requirements, laboratory diagnostic testing guidance, and infection control, antiviral treatment and prophylaxis recommendations.

New developments since Health Alert # 13

New York City Epidemiologic Update
• Diagnostic testing at the Centers for Disease Control and Prevention (CDC) has now confirmed 49 cases of Swine-Origin Influenza A (H1N1) (S-OIV) in New York City residents. All confirmed cases to date are epidemiologically linked to the outbreak among students and staff at the St. Francis Preparatory High School in Queens (n=47) or have an epidemiologic link to Mexico (n=2). Seven probable cases are currently under investigation.
o A probable case in Suffolk County does not have any known links to the St. Francis outbreak or Mexico suggesting likely exposure in a community setting.
o To date, illness in the United States and in New York City continues to be no more severe than usual seasonal influenza, with the overwhelming majority of diagnosed patients having had mild illness.
o The DOHMH is conducting active surveillance for severe febrile unexplained respiratory illness in all NYC hospitals, and to date has identified only two patients who have been hospitalized in New York City with probable or confirmed swine influenza. One of these patients has been discharged and the other is improving.
o DOHMH investigation of the S-OIV outbreak at St. Francis Preparatory High School:
o Among the 47 confirmed cases epidemiologically linked to St. Francis Preparatory High School, 44 have been interviewed. The median age w as 16 years (range 15-22). The most frequently reported symptoms included cough (43, 98%), subjective fever (41, 93%), fatigue (39, 89%), headache (37, 84%), chills (36, 82%), sore throat (36, 82%), runny nose (35, 80%), and muscle aches (35 (80%). Nausea, diarrhea, abdominal pain, shortness of breath and joint pain were also reported, but less frequently. At the time of the interview 37 (84%) reported that their symptoms were stable or improving and 4 (9%) reported complete resolution of symptoms. Only one reported having been hospitalized briefly, for syncope.
o An on-line survey of all students (N=2686) and staff (N=228) at the school is ongoing. Preliminary results from the on-line school survey and passive surveillance indicate widespread mild illness with hundreds of students and many staff reporting symptoms which meet the case definition for ILI with illness onset peaking on April 23rd and declining sharply thereafter. Secondary transmission to household con tacts was reported in approximately 8% of households responding to the survey.
o Given the evolving epidemiology of this outbreak in NYC and elsewhere, the number of NYC cases is expected to increase in the coming days and it is likely we will start to see evidence of community transmission in NYC unrelated to the high school outbreak. Updated case numbers and guidance will be issued in subsequent alerts.

• Routine NYC emergency department syndromic surveillance shows that fever and influenza-related emergency room visits began to increase on April 25, 2009, have increased on a daily basis, and have been higher than in past seasons. The increase is most dramatic among persons aged 18-59 years. It is unknown at this time whether the increase is due to changes in care-seeking behavior among persons with influenza-like illness or to an actual increase in influenza-like illness in the community.

US and Global Epidemiologic Update
• As of 3 pm on 4/29/2009, 9 1 cases have been confirmed in 14 states across the US, including one death in a 23 month old Texas child with an underlying high risk medical condition.
• Confirmed cases of S-OIV have been reported from an increasing number of countries across the globe. Today the World Health Organization (WHO) elevated the pandemic influenza alert level to 5, indicating that widespread human infection is occurring and a pandemic is imminent. The WHO uses a 6 point scale to assess the pandemic threat level.

Updated Antiviral Treatment and Prophylaxis Guidance
• The Food and Drug Administration (FDA) has issued an emergency use authorization for oseltamivir and zanamivir, authorizing the use of oseltamivir for treatment and prophylaxis of patients less than one year of age. Dosage recommendations for children less than 1 year of age are available at http://www.cdc.gov/swineflu/childrentreatment.htm  FDA has also authorized the use of both oseltamivir and zanamivir f or use at later time points (i.e., for patients with severe disease who have been symptomatic for more than 2 days).
• Treatment and prophylaxis: Oseltamivir stocks in some pharmacies are reportedly low, although the manufacturer reports adequate supplies, and local stocks are expected to increase. Clinicians are asked to exercise prudent judgment in prescribing oseltamivir for patients with mild ILI who do not have underlying medical conditions. Prescribing oseltamivir for purposes of personal stockpiles is strongly discouraged.

Home Management of Persons with Suspected, Probable or Confirmed S-OIV
• Persons with suspected, probable or confirmed S-OIV continue to be advised to stay home for 7 days after symptom onset or 24-48 hours after symptom resolution, whichever is longer. Patients should cover their mouths and noses with a tissue or handkerchief when coughing or sneezing, and should wash their hands with soap and water frequently.
• We recommend that home care for persons with mild ILI be given by one primary caregiver if possible, and that the patient should be separated to the extent possible from other members of the household, preferably in a separate bedroom. The caregiver should wear a mask, either surgical or N95, when close contact with the ill person is unavoidable. The ill person should also wear a surgical mask when close contact with other individuals in the home is unavoidable.


Surveillance and Reporting
• We continue to ask NYC providers to report hospitalized patients with severe, unexplained febrile, respiratory illness to the Provider Access Line at 1-866-NYC-DOH1 (1-866-692-3641). Providers should continue to test only patients with severe febrile respiratory illness for influenza A, using a commercially available rapid test, PCR or immunofluorescence test (e.g., DFA or IFA).
• In order to ensure that sufficient laboratory reso urces are available, testing at the Public Health Laboratory will only be approved for severe cases that are first reported to DOHMH via the Provider Access Line. DOHMH staff will evaluate the case and advise whether testing for S-OIV at the Public Health Laboratory is indicated. DOHMH will facilitate specimen transport and testing for cases when testing is indicated.
• The New York City case definitions for suspected, probable or confirmed cases are unchanged.

Guidelines for management of patients with mild influenza-like illness in New York City and infection control are unchanged. Please see the Health Department’s website at www.nyc.gov/health  for more information on its Swine Flu page, including educational materials for patients on respiratory and hand hygiene and STOP triage posters for waiting areas in clinics and emergency departments.

The CDC is updating guidance on its website daily. Please see www.cdc.gov/swineflu  for updated national rec ommendations.

To contact the Health Department, including to report suspected cases of swine influenza in hospitalized patients and arrange for specimen testing, please call the Provider Access Line at 866-NYC-DOH1. This number is also available for questions or consultations by providers.

As always, we appreciate the cooperation of the medical community in New York City and will update you with further information when it becomes available.

Sincerely,

The Swine Influenza Investigation Team
New York City Department of Health and Mental Hygiene