April 25 2009 Update from NYC Dept of Health on Swine Flu

2009 New York City Department of Health and Mental Hygiene (NYC DOHMH) Health Alert #11: Swine Influenza Update

Please distribute to staff in the Departments of Critical Care, Emergency Medicine, Family Practice, Geriatrics, Internal Medicine, Infectious Disease, Infection Control, Pediatrics, Neonatal Units, Nurseries, Pulmonary Medicine and Laboratory Medicine

April 25 , 2009

PLEASE NOTE: This is a rapidly evolving situation. This alert provides interim guidance. Guidance is likely to change in the upcoming days and weeks as more information becomes available.

• Swine influenza is suspected as the cause of a large outbreak of influenza A at St. Francis Preparatory High School in Queens. Specimens obtained from students at the school have been confirmed as influenza A, and are unsubtypeable as either H1 or H3 at the NYC Public Health Laboratory. This meets the case definition for probable swine influenza (see CDC case definitions below).
o To date, all illnesses appear to have been mild and no cases have been hospitalized.
o Samples are being sent to CDC tonight to determine if this outbreak is due to swine influenza. Results will be available tomorrow (Sunday).
o At this time, we are recommending antiviral treatment with oseltamivir or zanamavir as follows for persons associated with the school:
§ Severe influenza-like illness (ILI) or other severe febrile respiratory illness in a student, teacher, staff, or in any close contacts (e.g., household) of someone who attends or works at the school.
§ For patients with mild illness, treatment is only recommended for people who also have underlying conditions that increase the risk for more severe illness due to influenza (listed below). Mild illness should be treated only if treatment can be started within 48 hours of symptom onset.
o At this time, prophylaxis is only being recommended for the following contacts of ill persons associated with the school:
§ Healthcare workers who provided care to ill patients, and who either were not using or had a breach in appropriate personal protection when caring for patients or obtaining specimens
§ Asymptomatic household and other close contacts of ill persons who are at higher risk for complications of influenza (listed below).
• Reporting and management of other NY C hospitalized patients with severe, unexplained febrile, respiratory illness:
o Immediately report all patients with severe, unexplained febrile respiratory illness to the Provider Access Line at 1-917-438-9766.
o Test patients with severe febrile respiratory illness for influenza A using a commercially available rapid test, PCR or immunofluorescence test (e.g., DFA or IFA).
o Personal protective measures should be taken by medical personnel caring for or obtaining specimens from patients being tested for influenza or who have suspected, probable or confirmed swine influenza. See http://www.cdc.gov/swineflu/guidelines_infection_control.htm.
o If hospitals are not able to conduct initial rapid influenza testing, please contact the DOHMH to arrange for testing for influenza A.
• Management of patients with mild influenza-like illness
o Patients with mild illness should be encouraged to stay home until 24-48 hours after resolution of symptoms.
§ Pat ients should be instructed to wash their hands frequently, cough into a tissue or sleeve (not into bare hands or onto another person), dispose of tissues in the trash, and stay home from school or work until 24-48 hours after illness is resolved.
o At this time, we are not recommending routine influenza testing and/or antiviral treatment for persons with mild influenza-like illness, unless they meet the usual criteria for empiric influenza treatment based on underlying illnesses that put them at higher risk for complications of any type of influenza.
• According to the CDC, vaccination for seasonal influenza is unlikely to be effective for prevention of swine influenza.
• Additional information on the outbreaks in the US and Mexico, including NYC, as well as further clinical guidance will be provided as it becomes available. For updated information on the national situation, see http://www.cdc.gov/swineflu/general_info.htm.

Dear Colleagues,

On April 23, a high school in Queens was noted to have an outbreak of mild febrile respiratory illness that was confirmed last night to be caused by influenza A. Specimens were sent to the NYC Public Health Laboratory and were untypeable for human H1 or H3 strains, meeting the CDC case definition for probable swine influenza. These specimens are being forwarded to CDC today for further testing to determine if these infections are due to swine influenza. Results should be available tomorrow. The high school has approximately 2,700 students, and as of yesterday, 200 children were reported to be ill, mostly with mild influenza-like symptoms (fever, cough, and/or sore throat). None of the cases were severe or required hospitalization.

In the United States, there are currently 6 California residents and 2 Texas residents who have been diagnosed with swine influenza A (H1N1) virus infection; all of these patients had mild illness (only one hospitalization) and all have recovered. Isolates from California and Texas have been found to be susceptible to the neuraminidase inhibitors (oseltamivir and zanamavir) but resistant to the adamantanes (amantadine and rimantadine). In addition, there has been an outbreak of respiratory illness in Mexico, which has been confirmed as at least partly due to swine influenza; clinical and epidemiologic details of this outbreak are still pending, but preliminary reports are of thousands of cases and approximately 70 deaths.

Surveillance for Swine Influenza in Hospitalized Cases Citywide:
The NYC Health Department is now prioritizing its surveillance efforts for swine influenza on identifying potential cases of febrile, respiratory illness in hospitalized patients, in order to rapidly identify and confirm potential cases with more severe illness. Therefore, DOHMH requests that providers seeing patients with acute febrile respiratory illness only test those patients who are either currently hospi talized or are being admitted to the hospital with unexplained febrile respiratory illness. These patients should be tested for influenza using either a commercial rapid test, or direct or indirect immunofluorescence. Patients who test positive for influenza A should be reported to DOHMH and have specimens referred to DOHMH for further testing to determine whether the influenza A can be subtyped. See contact information below. DOHMH will arrange for transportation of clinical specimens to the Public Health Laboratory. See attached instructions for collecting and submitting laboratory diagnostic specimens for swine influenza testing. Nasopharyngeal swabs are the preferred specimens for influenza testing in the current swine influenza context.

Management of Persons with Milder Influenza-like Illness
At this time, providers assessing patients with mild febrile respiratory illness in clinical settings, including emergency departments, should not test for influenza and should not administer antiviral medications for presumptive therapy, unless patients meet the usual criteria for empiric influenza treatment based on underlying illnesses (listed below) that put them at higher risk for complications of any type of influenza. These patients may be sent home with instructions to stay at home until 24-48 hours after their symptoms resolve and instructed on the importance of hand and respiratory hygiene. Instructions should be given to seek medical care with worsening of symptoms.

Infection Control
For current recommendations on infection control in medical care facilities, see http://www.cdc.gov/swineflu/guidelines_infection_control.htm.

Antiviral Treatment and Prophylaxis Guidelines
Swine influenza viruses identified in this outbreak to date have been susceptible to both oseltamivir and zanamivir. Antiviral therapy with one of these agents should be initiated empirically for patients currently hospitalized with sever e unexplained febrile respiratory illness, pending testing for swine influenza. See http://www.cdc.gov/swineflu/recommendations.htm for specific guidelines. This document also includes detailed guidance on antiviral prophylaxis.

The Health Department requests that providers also immediately report any clusters of influenza-like illness in medical facilities, congregate settings such as long-term care facilities, or schools.

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 1- 917-438-9766. 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,

Scott A. Harper, MD, MPH, MSc
Medical Epidemiologist
Zoonotic, I nfluenza, & Vectorborne Diseases Unit
Bureau of Communicable Disease

Annie Fine, MD
Medical Director
Zoonotic, Influenza, & Vectorborne Diseases Unit
Bureau of Communicable Disease

Definitions of Respiratory Illness

1. Acute respiratory illness
Recent onset of at least two of the following:
1. rhinorrhea or nasal congestion
2. sore throat
3. cough
4. fever or feverishness
2. Influenza-like illness: fever >37.8°C (100°F) plus cough or sore throat
Case Definitions for Infection with Swine Influenza A (H1N1) Virus
1. A Confirmed case of swine influenza A (H1N1) virus infection is defined as a person with an acute respiratory illness with laboratory confirmed swine influenza A (H1N1) virus infection at CDC by one or more of the following tests:
1. real-time RT-PCR
2. viral culture
3. four-fold rise in swine influenza A (H1N1) virus specific neutralizing antibodies
2. A Pr obable case of swine influenza A (H1N1) virus infection is defined as a person with an acute respiratory illness with an influenza test that is positive for influenza A, but H1 and H3 negative.
3. A Suspected case of swine influenza A (H1N1) virus infection is defined as:
1. A person with an acute respiratory illness who was a close contact to a confirmed case of swine influenza A (H1N1) virus infection while the case was ill OR
2. A person with an acute respiratory illness with a recent history of contact with an animal with confirmed or suspected swine influenza A (H1N1) virus infection OR
3. A person with an acute respiratory illness who has traveled to an area where there are confirmed cases of swine influenza A (H1N1)


Conditions which increase the risk of severe influenza infection
• chronic pulmonary, cardiovascular, renal, hepatic, hematological, or metabolic disorders,
• immunosuppression,
• compromised respiratory function , including conditions which increase the risk for aspiration,
• long-term aspirin therapy
• pregnancy
• age > 65 years
• age < 2 years