Hospital-acquired influenza: Seek and ye shall find

Abstract

BACKGROUND: In a 212-bed acute care community hospital that is part of a large academic teaching center in New York City, three inpatients acquired influenza A during their hospitalizations in December 2004. The first case was on a geriatric unit; the other two were on a telemetry unit. No hospital-acquired (HA) influenza cases had previously been described in this hospital. The New York City Department of Health had received no comparable reports from any other acute care facilities in the area. METHODS: All cases were diagnosed by nasopharyngeal swabs sent for enzyme immunoassay (EIA), direct fluorescent antibody (DFA), and viral culture. The first HA influenza patient was a readmission. As a result, another symptomatic inpatient was tested (positive). Surveillance testing was then performed and a third case was identified. The emergency department staff increased their testing for community-acquired (CA) influenza; patients presenting with fever over 100°F and respiratory symptoms were swabbed. Those being admitted were placed in single rooms on droplet isolation. Inpatients who spiked fevers and exhibited respiratory symptoms were swabbed and isolated. Positively identified influenza patients were cohorted and treated with amantadine or oseltamivir. Staff members exposed to non-isolated flu patients were given prophylaxis unless they had been vaccinated at least 2 weeks before. RESULTS: No more HA cases occurred. We were unable to identify sources for the three HA cases. Two of the three had received influenza vaccinations greater than 2 weeks before their admissions. The rate of CA influenza admissions rose from 0.45 per 100 admissions in December 2003, to 4.19 per 100 admissions in December 2004. Resources were stretched thin, including single rooms and surgical masks. CONCLUSION: A heightened degree of suspicion and testing led to the diagnosis of three HA cases of influenza and improved recognition of CA cases. This was especially important during a year of influenza vaccine shortage. Increased testing of symptomatic inpatients should be performed during influenza season to monitor for nosocomial transmission. BACKGROUND: In a 212-bed acute care community hospital that is part of a large academic teaching center in New York City, three inpatients acquired influenza A during their hospitalizations in December 2004. The first case was on a geriatric unit; the other two were on a telemetry unit. No hospital-acquired (HA) influenza cases had previously been described in this hospital. The New York City Department of Health had received no comparable reports from any other acute care facilities in the area. METHODS: All cases were diagnosed by nasopharyngeal swabs sent for enzyme immunoassay (EIA), direct fluorescent antibody (DFA), and viral culture. The first HA influenza patient was a readmission. As a result, another symptomatic inpatient was tested (positive). Surveillance testing was then performed and a third case was identified. The emergency department staff increased their testing for community-acquired (CA) influenza; patients presenting with fever over 100°F and respiratory symptoms were swabbed. Those being admitted were placed in single rooms on droplet isolation. Inpatients who spiked fevers and exhibited respiratory symptoms were swabbed and isolated. Positively identified influenza patients were cohorted and treated with amantadine or oseltamivir. Staff members exposed to non-isolated flu patients were given prophylaxis unless they had been vaccinated at least 2 weeks before. RESULTS: No more HA cases occurred. We were unable to identify sources for the three HA cases. Two of the three had received influenza vaccinations greater than 2 weeks before their admissions. The rate of CA influenza admissions rose from 0.45 per 100 admissions in December 2003, to 4.19 per 100 admissions in December 2004. Resources were stretched thin, including single rooms and surgical masks. CONCLUSION: A heightened degree of suspicion and testing led to the diagnosis of three HA cases of influenza and improved recognition of CA cases. This was especially important during a year of influenza vaccine shortage. Increased testing of symptomatic inpatients should be performed during influenza season to monitor for nosocomial transmission.