An Estimate of the Incidence of Influenza-Like Illness During the Influenza Pandemic of 2009

作者：Bellido Blasco Juan B^*; Pardo Serrano Francisco; Ballester Rodriguez Isabel; Arnedo Pena Alberto; Dolores Tirado Balaguerb M; Angeles Romeu Garcia M; Silvestre Silvestre Ester; Meseguer Ferrer Noemi; Herrero Carot Concha; Cayla Buqueres Joan A

来源：Archivos de Bronconeumologia, 2015, 51(8): 373-378.

DOI：10.1016/j.arbres.2014.07.009

• Influenza-like syndrome
• Incidence
• Estimation
• Capture-recapture
• Influenza pandemic
• Influenza

Introduction: The influenza pandemic of 2009 had a great social impact. Many health resources were devoted to the care, prevention and surveillance of this disease. Epidemiological surveillance is based on the reporting of cases of influenza-like illness (ILI) and confirmed influenza cases. The objective was to estimate the true incidence of ILI during the influenza pandemic of 2009.
Methods: The capture-recapture method was applied during the month of highest influenza incidence in Castellon. Two notification systems were used: (i) electronic reporting of Notifiable Diseases (ND), and (ii) laboratory-based (LAB) data collection. Estimates were made by stratifying by age group and week. Independence coefficients were calculated for those strata.
Results: No dependence was found between stratification variables and the reporting system. A total of 7,181 ND cases and 524 LAB cases were identified, of which 211 were recorded in both systems. The estimated total of cases was 17,785 in a single month. In the study period, almost 4% of people in the area suffered flu symptoms (cumulative incidence), with 1% being affected each day (daily prevalence). The sensitivity of the ND system was 40%, i.e., the percentage of patients seeking primary care.
Conclusions: To obtain an estimate of the actual incidence of influenza-like illness in the population during a pandemic period, the number of medical consultations should be multiplied by a factor of 2.5. This factor is lower than that estimated for periods without pandemic alert.

• 出版日期2015-8