THE MANAGEMENT OF A HOSPITAL-ACQUIRED INFLUENZA AH1N1 OUTBREAK IN ONCOLOGICAL PATIENTS. A CASE SERIES REPORT

Despite prevailing concerns about the risk of influenza infection in immunocompromised patients, the actual rate and effect of infection in this population are not well characterized. We report a fulminant course of a hospital-acquired influenza AH1N1 infection in a public hospital for oncological patients. From a total of 60 persons (40 patients and 20 symptomatic health care workers - HCWs) screened by collecting nasal and pharyngeal swab samples, a number of 33 (24 patients and 9 HCWs) were found positive for respiratory viruses. Of them, 23 cases had influenza A virus (20 patients and 3 HCWs), all contacts with in-hospital influenza cases. The 4 first cases were diagnosed with influenza type A and subtype H1N1. In the epidemiological context we presumed all the other influenza A patients had the subtype H1N1. 9 influenza A patients were managed in the ICU: 5 patients for severe and 4 patients for mild/moderate ARDS. Oseltamivir treatment was instituted in all symptomatic patients and HCWs and in asymptomatic high-risk immune-compromised contacts. All ICU influenza patients and contacts were strictly isolated, had dedicated vaccinated HCWs wearing protective equipment and received oseltamivir treatment for prolonged periods until virus clearance or death. 5 patients died: 3 patients due to severe ARDS and intractable hypoxemia and 2 patients due to unrelated causes. The influenza-related death occurred in the first patients due to late diagnosis and late antiviral treatment institution.  The epidemiological measures are described along with the hospital-acquired influenza outbreak course.