Control of an influenza outbreak in a long-term care facility with a high immunization rate

BACKGROUND/OBJECTIVES: Influenza prevention is a key component of long-term care (LTC) infection control. We report our experience with influenza control in a 326-bed LTC facility. As of January 1, 2005, the patient immunization rate was 96% (247/258); the immunization rate of direct care providers was 70%. From January 10-13, 2005, five patients on three units were identified with influenza; three were confirmed as influenza A via rapid antigen testing and two presumptive. Four of five patients received an influenza immunization between October 14 and November 15, 2004; the other patient refused. Symptoms included fever (100.3–103°F), malaise, cough, myalgia, chills, and infiltrate or effusion on chest x-ray. Four of five patients were admitted to acute care for treatment. Blood cultures were negative in all five patients, three of three had negative urinary pneumococcal and Legionella antigen tests; bacteriologic cultures did not identify other infection. On January 11, 2005, (after identification of two cases), infection control met with key staff to implement a control plan. METHODS: The plan included the following: 1) Patients were confined to their units until no further cases were identified (3 days). 2) Patients with suspected or confirmed cases of influenza were placed in droplet/contact precautions until afebrile for 48 hours. 3) All patients received prophylaxis (100 mg amantadine oral daily × 14 days). 4) Temperatures were recorded every shift, with elevations reported to infection control. 5) Nonimmunized direct care providers on units with influenza patients were offered amantadine prophylaxis; 20 employees opted for prophylaxis. 6) Posting of “respiratory etiquette” signs was expanded to unit and building entrances. RESULTS: After January 13, 2005, no further cases of influenza were identified. One patient death resulted. There were no employee “call offs” due to influenza. No employees experienced side-effects related to amantadine prophylaxis. Four weeks prior to initiation of amantadine, patient falls ranged from 3 to 11 per week (mean 6). While patients were receiving amantadine, falls increased (week 1, 9 falls; week 2, 21). CONCLUSIONS: Even with a high rate of immunization, influenza surveillance is a major component of a LTC infection control program. The key features of our successful intervention were 1) immediate identification of flu-like illness by staff, 2) rapid antigen testing to confirm transmission, and 3) immediate institution of countermeasures, including amantadine prophylaxis.