Résumé
Objective To analyze the correlation between detection of influenza pathogenic subtypes and epidemic situation in Hefei City during the surveillance years of 2015-2021, and to provide references for developing influenza prevention and control strategies. Methods The relevant data of influenza-like illness (ILI) surveillance, influenza etiology, and outbreak/cluster outbreaks reported from influenza surveillance sentinel hospitals in Hefei City from 2015 to 2021 in the China Influenza Surveillance Information System were analyzed. The statistical analysis was carried out. Results A total of 3 332 553 outpatient and emergency visits in 2 sentinel hospitals were reported in Hefei City from 2015 to 2021, of which 139,082 were ILI cases, accounting for 4.17%. The monthly proportion ranged from 1.60% to 7.15%. A total of 14 663 ILI specimens were submitted for detection, the submission rate was 10.54%, and the positive rate of influenza virus detection was 11.30%. There was no correlation between the proportion of monthly influenza like cases and the detection rate (rs=0.176, P=0.107). The composition ratio of each subtype of influenza virus varied greatly, showing diversified seasonality, and the epidemic strains changed constantly. The Victoria subtype (BV subtype) was dominant (40.21%). There was a moderate correlation between the positive rate of ILI in sentinel hospitals and the number of outbreaks per month (rs=0.696, P=0.000). There was a strong correlation between the monthly number of outbreaks and the detection rate (rss=0.696, P=0.000). There was a strong correlation between influenza A virus H3 subtype and BV subtype (rs -H3=0.686, P=0.030; rs -BV=0.632, P=0.000). There was a moderate correlation between the new A1 subtype and B Yamagata subtype (rs -new A H1=0.481, P=0.000 0; rs -BY=0.515, P=0.000). Conclusion There are two epidemic peaks in spring and winter in Hefei. Influenza subtypes are diverse. The results of ILI etiology can predict the outbreaks of different subtypes of influenza. Prediction and surveillance should be used for influenza control and outbreak management in a timely manner.