Infection Control Precautions and Guidance for Contacts
Avian H5N1 Influenza Transmission
Most information on the modes of influenza transmission from person to person is indirect and largely obtained through observations during outbreaks in healthcare facilities and other settings (e.g., cruise ships, airplanes, schools, and colleges); the amount of direct scientific information is very limited. However, the epidemiologic pattern observed is generally consistent with spread through close contact with infected persons (i.e., exposure to large respiratory droplets, direct contact, or near-range exposure to aerosols). While some observational and animal studies support airborne transmission through small particle aerosols, there is little evidence of airborne transmission over long distances or prolonged periods of time (as is seen with tuberculosis). The relative contributions and clinical importance of the different modes of influenza transmission are currently unknown. Nevertheless, for the following reasons, the Centers for Disease Control and Prevention (CDC) has released revised
"interim" enhanced infection control precautions for suspected or confirmed cases of avian influenza:
- The risk of serious disease and increased mortality from highly pathogenic avian influenza may be significantly higher than from infection with human influenza viruses.
- Each human infection represents an important opportunity for avian influenza to further adapt to humans and gain the ability to transmit more easily among people, with the possibility that a pandemic strain might emerge.
For patients meeting clinical and epidemiologic criteria for suspected avian H5N1 influenza infection, but who have not yet tested positive for avian H5N1 influenza, the following infection control procedures should be followed:
*Respirators should be used in the context of a complete respiratory protection program as required by the Occupational Safety and Health Administration (OSHA). This includes training, fit-testing, and fit-checking to ensure appropriate respirator selection and use. To be effective, respirators must provide a proper seal with the wearer's face. Detailed information on a respiratory protection program is provided at this OSHA web page.
- All patients who present to a health-care setting with fever and respiratory symptoms should be managed according to recommendations for Respiratory Hygiene and Cough Etiquette and questioned regarding their recent travel history.
- Patients with a history of travel within 10 days to a country with avian influenza activity, who report a risk exposure to H5N1 in birds or humans and who are being hospitalized with a severe febrile respiratory illness, or are otherwise under evaluation for avian influenza, should be managed using isolation precautions like those recommended for patients with known Severe Acute Respiratory Syndrome (SARS). These include:
- Standard Precautions
- Pay careful attention to hand hygiene before and after all patient contact or contact with items potentially contaminated with respiratory secretions
- Contact Precautions
- Use gloves and gown for all patient contact
- Use dedicated equipment such as stethoscopes, disposable blood pressure cuffs, disposable thermometers, etc.
- Disinfect surfaces frequently
- Droplet Precautions
- Wear goggles or a face shield when within 3 feet of infected persons
- Place surgical mask on patient when transporting to areas of the facility where infection of other persons might occur
- Airborne Precautions
- Place the patient in a single airborne isolation room (AIIR). Such rooms should have monitored negative air pressure in relation to corridor, with 6 to 12 air changes per hour (ACH), and exhaust air directly outside or have recirculated air filtered by a high efficiency particulate air (HEPA) filter. If an AIIR is unavailable, contact the health-care facility engineer to assist or use portable HEPA filters (see Environmental Infection Control Guidelines) to augment the number of ACH.
- Use a fit-tested respirator, at least as protective as a National Institute of Occupational Safety and Health (NIOSH)-approved N-95 filtering facepiece (i.e., disposable) respirator, when entering the room.*
- Strict attention to airborne precautions are most essential when performing procedures that are more likely to generate small particle aerosols, such as intubation, bronchoscopy or sputum induction.
For additional information regarding these and other health-care isolation precautions, see the Guidelines for Isolation Precautions in Hospitals. These precautions should be continued for 14 days after onset of symptoms or until either an alternative diagnosis is established or diagnostic test results indicate that the patient is not infected with avian H5N1 influenza A virus. Patients managed as outpatients or hospitalized patients discharged before 14 days with suspected avian influenza should be isolated in the home setting on the basis of principles outlined for the home isolation of SARS patients (see the CDC's guidance document).
Please note that the CDC guidance is considered "interim" and may change, especially if epidemiologic data from the current avian H5N1 influenza outbreak becomes available and demonstrates that small particle airborne transmission is unlikely so that use of AIIRs and N95 respirators is not necessary.
back to top
Patients Testing Positive for Avian H5N1 Influenza
Infection control precautions for confirmed avian H5N1 influenza patients are the same as for those with suspect disease. Standard, contact, droplet, and airborne precautions should be used by healthcare workers in contact with the patient for 14 days after symptom onset in the patient.
back to top
Management of Contacts of Suspect Cases
Close contacts (e.g., household, sexual, etc.) of suspected or confirmed avian influenza patients should be managed on a case-by-base basis. Please contact the DOHMH Bureau of Communicable Disease (212-788-9830) during business hours, or the Poison Control Center (800-222-1222) at all other times for consultation.
back to top