Objective To understand the pathogenic spectrum and epidemiological characteristics of severe acute respiratory infection （SARI） in adult inpatients in Yangpu District， Shanghai， China， in order to explore strategies for the prevention and treatment of respiratory infectious diseases.

Methods Individual cases were from adult inpatients with SARI in Yangpu District， Shanghai， China from January 2019 to July 2021. Their respiratory samples were collected for etiological pathogen testing.

Results A total of 681 SARI cases were enrolled for sampling and lab testing. Among them， 79.00% were aged 60 years and older， and 75.48% had confirmed chronic disease history. A total of 163 infection inpatients （23.94%） were positive for at least one pathogen. The pathogens identified most frequently were influenza A virus （6.75%）， followed by rhinovirus/enterovirus （3.23%）， parainfluenza virus （PIV） （2.79%）， Mycoplasma pneumoniae （2.35%）， coronavirus （CoV） （2.06%）. The positive rates of adenovirus （AdV）， human metapneumovirus （hMPV）， respiratory syncytial virus and bocavirus were all less than 2%. Bacterial strains were identified in eleven SARI cases， including Staphylococcus aureus and Pseudomonas aeruginosa （4 strains）， Klebsiella pneumoniae （3 strains）. Legionella pneumophila was detected in 9 cases （1.32%） and Bordetella pertussis in 5 cases （0.73%）. Two pathogens were co-detected from 11 cases， accounting for 1.62% of 163 positive cases. The most common co-detected pathogens were influenza A virus and other pathogens， accounting for 54.55% of the mixed infection. The positive rates of pathogens were not significantly different between less than 60 years old and over 60 years old groups except for Bordetella pertussis， adenovirus and Mycoplasma pneumonia（P<0.05）. Influenza virus had epidemic peak in winter and spring， but not in summer from 2019 to 2021.

Conclusion Various respiratory pathogens are detected from adult SARI cases. It is mainly influenza virus， with co-detected pathogens and rare pathogens. This study provides helpful information for targeted prevention and control measures including vaccination.