Analysis on #epidemiological characteristics of #influenza and #genetic characteristics of influenza virus in 2023-2024 surveillance year in #Shandong Province
Abstract Objective : To analyze the epidemiological, etiological and genetic characteristics of influenza virus in Shandong Province during 2023-2024. Methods : The surveillance data of influenza-like illness (ILI) in sentinel hospitals in Shandong from 2023 to 2024 were collected and analyzed. The isolated influenza strains with hemagglutination titers ≥8 were selected for antigenicity analysis , drug susceptibility test, gene sequencing and evolutionary analysis . Results : From 2023 to 2024, the positive rate of influenza virus in Shandong was 8.51% (23 663/277 995), the highest positive rate was in the age group of 5-14 years (15.78%, 6 073/38 478), and the highest positive rate was in the 49th week (35.86%, 2 264/6 313). Both antigenicity analysis and evolutionary analysis showed that the A(H1N1)pdm09 subtype and B(Victoria) strain had good matching effect and close evolutionary distance with the 2023-2024 surveillance year vaccine strain. The A(H3N2) ...