Influenza outbreak management on a locked behavioral health unit

In January 2006, 8 patients on a locked behavioral health (BH) ward were identified with influenza-like illness (ILI) based on syndrome of fever, malaise, myalgia, cough, and rhinitis. Two patients initially had rapid antigen testing positive for influenza and confirmed by polymerase chain reaction. All patients present on the ward (N=26) had been ordered influenza immunizations 6 weeks earlier: 46% (12/26) were immunized, 42% (11/26) refused, 12% (3/26) had no record of immunization. All direct care staff who worked on the unit during the outbreak had been offered immunizations in the fall: 55% (22/40) were immunized.

When first symptoms were identified, provider notified infection control nurse and hospital epidemiologist, who instituted control measures: patients were confined to unit, unit was closed to admissions, nonimmunized asymptomatic patients were offered immunization, temperatures were recorded every 4hours, and nonimmunized providers were offered immunizations and prophylaxis. Patients with ILI were either admitted to acute care and placed in Droplet/Contact Precautions until afebrile for 48hours or managed on the unit with modified isolation. All patients remaining on the unit were instructed in hand hygiene and respiratory etiquette; asymptomatic patients were offered oseltamivir phosphate prophylaxis; and previously nonimmunized patients and staff were again offered the vaccine.

Twenty-six patients and 28 staff were on the unit during the outbreak. Eight patients and 8 staff members reported ILI within 5 days. Of the ill patients, 3 had been immunized, 5 had not (2 refused, 3 reason unclear presumed to have refused), and 4 were admitted to acute care and placed in Droplet/Contact Precautions until asymptomatic for 48hours. Of 22 patients who remained on the unit, 4 were symptomatic; 18 asymptomatic patients took prophylaxis, and 1 refused; 8 (89%) patients who had earlier refused vaccine were immunized. Of the 40 staff members, 55% (22/40) were immunized, and 20% (8/40) were symptomatic (all presumptive, encouraged to remain off duty). Fifty percent (4/8) of symptomatic staff had been immunized. After 7 days, no new cases had been identified, and the unit was reopened to admissions. No ill effects resulted from the prophylaxis.

Prompt detection of ILI and institution of control measures effectively contained the outbreak; the relatively high immunization rates among both patients and staff helped curtail spread. Refusal of immunization is a long-standing problem among BH patients and staff. Our study shows importance of immunization in preventing outbreaks in inpatient BH settings. Recommendations included development of more aggressive immunization campaign for patients and staff who historically refuse and continued high priority for provider vigilance in immunization campaign and surveillance for symptoms.