Control measures to thwart nosocomial flu

The Centers for Disease Control and Prevention has recently addressed the issue of influenza infection control in updated guidelines for health care workers and for patient isolation, which are summarized as follows.1,2

Nosocomial transmission of influenza has been reported in acute and long-term care facilities. Transmission has occurred from patients to health care personnel, from health care personnel to patients, and among health care personnel. Influenza is believed to be primarily transmitted from person to person by direct deposition of virus-laden large droplets onto the mucosal surfaces of the upper respiratory tract of an individual during close contact with an infected person, as well as by droplet nuclei or small-particle aerosols. While the extent of transmission by virus-contaminated hands or fomites is not known, it is not the primary mode of transmission. The incubation period of influenza is usually one to five days, and the period of greatest communicability is during the first three days of illness. However, virus can be shed before the onset of symptoms and up to seven days after illness onset.

• Administer influenza vaccine annually to all personnel, including pregnant women, before the influenza season, unless otherwise contraindicated. Consider the use of antiviral postexposure prophylaxis for unvaccinated health care personnel during institutional or community outbreaks of influenza.

• Consider excluding personnel with acute febrile respiratory infections or laboratory evidence of epidemiologically significant viruses from the care of high-risk patients (e.g., neonates, young infants, patients with chronic obstructive lung disease, and immunocompromised patients) during community outbreaks.

• In addition to standard precautions, use droplet precautions for a patient known or suspected to be infected. Place the patient in a private room. When a private room is not available, place the patient in a room with a patient(s) who has active infection with the same microorganism but with no other infection (cohorting). When a private room is not available and cohorting is not achievable, maintain spatial separation of at least three feet between the infected patient and other patients and visitors. Special air handling and ventilation are not necessary, and the door may remain open.

• Wear a mask when working within three feet of the patient. Logistically, some hospitals may want to implement the wearing of a mask to enter the room. Limit the movement and transport of the patient from the room to essential purposes only. If transport or movement is necessary, minimize patient dispersal of droplets by masking the patient, if possible.


1. Centers for Disease Control and Prevention. Draft guideline for infection control in health care personnel, 1997; notice. 62 Fed Reg 47,276-47,327 (Sept. 8, 1997).

2. Garner JS, Hospital Infection Control Practices Advisory Committee. Guideline for isolation precautions in hospitals. Infect Control Hosp Epidemiol 1996; 17:53-80.