Objective:To analyze the epidemiological characteristics of influenza A virus (FluA), influenza B virus (FluB), and respiratory syncytial virus (RSV) in cases with influenza-like illness in the fever clinic of a tertiary hospital in Shanghai in order to provide reference for the prevention and control of influenza virus and RSV infections.Methods:Oropharyngeal swabs were collected from cases with influenza-like illness who were treated in Shanghai Pulmonary Hospital from February 2023 to May 2024. The nucleic acids of FluA, FluB, and RSV were detected by GeneXpert test. The demographic features including age and gender, and the epidemiological characteristics of viral infections and mixed infections in these patients were analyzed.Results:A total of 11 094 patients were tested for the nucleic acids of FluA, FluB, and RSV, and the positive rates were 36.82% (4 085/11 094), 9.70% (1 076/11 094), and 1.44% (160/11 094), respectively. During the period from February 2023 to May 2024, FluA mainly circulated in winter and spring, reaching its peak in March 2023 (74.51%, 766/1 028) and mainly affecting individuals aged 0 to 18 (45.62%, 198/434). FluB infection mainly occurred in winter, peaking in January 2024 (32.73%, 547/1 671) with the highest positive rate among individuals aged 19 to 44 (12.98%, 857/6 601). As few children were involved in this study, RSV infection was mainly detected in the elderly over 60 years old (3.19%, 94/2 950), and the positive rate was less than 5% every month. Co-infection of two viruses (24 cases) were occasionally detected.Conclusions:From 2023 to 2024, a large-scale influenza virus epidemic appears in Shanghai area, with FluA and FluB alternately being the dominant strain, and the positive rate of RSV remains at a low level, showing a sporadic pattern. The main age groups affected by different pathogens vary, and strengthened surveillance is still needed in the future.

Objective:To analyze the epidemiological characteristics of influenza A virus (FluA), influenza B virus (FluB), and respiratory syncytial virus (RSV) in cases with influenza-like illness in the fever clinic of a tertiary hospital in Shanghai in order to provide reference for the prevention and control of influenza virus and RSV infections.Methods:Oropharyngeal swabs were collected from cases with influenza-like illness who were treated in Shanghai Pulmonary Hospital from February 2023 to May 2024. The nucleic acids of FluA, FluB, and RSV were detected by GeneXpert test. The demographic features including age and gender, and the epidemiological characteristics of viral infections and mixed infections in these patients were analyzed.Results:A total of 11 094 patients were tested for the nucleic acids of FluA, FluB, and RSV, and the positive rates were 36.82% (4 085/11 094), 9.70% (1 076/11 094), and 1.44% (160/11 094), respectively. During the period from February 2023 to May 2024, FluA mainly circulated in winter and spring, reaching its peak in March 2023 (74.51%, 766/1 028) and mainly affecting individuals aged 0 to 18 (45.62%, 198/434). FluB infection mainly occurred in winter, peaking in January 2024 (32.73%, 547/1 671) with the highest positive rate among individuals aged 19 to 44 (12.98%, 857/6 601). As few children were involved in this study, RSV infection was mainly detected in the elderly over 60 years old (3.19%, 94/2 950), and the positive rate was less than 5% every month. Co-infection of two viruses (24 cases) were occasionally detected.Conclusions:From 2023 to 2024, a large-scale influenza virus epidemic appears in Shanghai area, with FluA and FluB alternately being the dominant strain, and the positive rate of RSV remains at a low level, showing a sporadic pattern. The main age groups affected by different pathogens vary, and strengthened surveillance is still needed in the future.