Epidemiological Surveillance of Influenza (H1N1) 2009 without Sentinel System

Abstract

Background: The objective is to explain the Galician influenza surveillance system and to present the results observed during the pandemic flu, where due to the lack of sentinel surveillance practices, other alternatives are used. Method: Data was collected from: 061 phone calls for flu and acute respiratory illness; notifiable diseases usual reporting system (SXNOE); virological surveillance; primary care and hospital records and was analyzed with Excell. Results: The first epidemic wave for A(H1N1)v according to 061 data was between week 39/2009 and 49/2009, and it peaked in week 44/2009, with a greater rate of accumulated calls was in the 5-19 age group. SXNOE showed a wave (week 39/2009 to 49/2009) and peaked in week 44/09. Virological surveillance included 6.181 samples with PCR-RT (31% were positive and peaked in week 44/09). Primary care registers showed a wave (week 39/2009 to 49/2009) which peaked in week 44/09 with the greatest rate of consultations was in the 5-19 age group. Between week 26/09 and week 17/2010, 698 patients were admitted with A(H1N1)v, with the highest hospitalization in week 44/09. Conclusions: The validity of the described surveillance systems is supported by the homogeneity of results, and they produced an equivalent wave (weeks 39/2009 to 49/2009) which peaked in week 44/2009 and showed the highest rate of consultations in the 5-19 age group. The 061 appears to be the most practical system to provide daily data.