Pandemic influenza A(H1)pdm09 in hospitals and intensive care units – results from a new hospital surveillance, Germany 2009/2010

OBJECTIVES The pandemic influenza A(H1)pdm09 (PI) was introduced to Germany in April 2009. The Robert Koch Institute (RKI) implemented a nationwide voluntary hospital sentinel surveillance for to assess the burden and severity of PI. SETTING Three modules were offered: a hospital module collected aggregated data from all hospital units on admissions and fatalities with and without PI; an intensive care module data on admissions, patient-days, and ventilated patient-days with and without PI; and a case-based module retrieved clinical patient data of PI cases. A in-patient with a PCR confirmation was defined as a PI case. Descriptive, trend, uni-, and multivariable analysis were performed. RESULTS Between week 49/2009 and 13/2010, the hospitals reported 103 (0.07%) PI cases among 159181 admissions and 59/16728 (0.35%) PI-related admissions in intensive care units (ICUs). The weekly average incidence decreased in hospitals by 21.5% and in ICUs by 19.2%. In ICUs, 1848/85559 (2.2%) patient-days were PI-related, 94.8% of those with mechanical ventilation. Case-based data on 43 recovered and 16 fatal PI cases were reported. Among recovered, 61% were admitted to ICUs, 51% were mechanically ventilated, and 16% received extracorporeal membrane oxygenation (ECMO). All fatal cases were admitted to ICUs and received mechanical ventilation, 75% ECMO. Fatal outcome was rather associated with complications than with underlying medical conditions. CONCLUSION The surveillance started shortly after the PI peak, which explains the small number of PI cases. The burden of PI disease was low, but higher in ICUs with a high proportion of severe cases needing ventilation and ECMO treatment. A continuous hospital surveillance system could be helpful to measure the burden of severe community-acquired infections.