Objective To investigate the changes in the pathogen spectrum of viral diarrhea in local pediatric inpatients as well as any variations in genotypes of major pathogens during the COVID-19 control period.

Methods Fecal samples were collected from the children <5 years who were hospitalized due to acute gastroenteritis in a pediatric hospital in Shanghai. PCR test was carried out to detect rotavirus， norovirus， sapovirus， astrovirus and enteric adenovirus， and then genotyping was performed for major pathogens.

Results Out of 546 samples， 37.55% tested positive for virus with the following positive rate ranking： norovirus GⅡ （22.16%）， group A rotavirus （16.12%）， astrovirus （2.93%）， enteric adenovirus （2.38%）， sapovirus （0.92%） and norovirus GⅠ （0.18%）. The predominant genotype within norovirus GⅡ were GⅡ.4［P31］ and GⅡ.4［P16］ with a proportion of 24.79% and 14.05% respectively. The detection rate of GⅡ.4［P31］ dropped significantly over the 2-year period （χ²＝16.140，P<0.001）. In addition， an emerging rotavirus genotype G8P ［8］， which was rarely found nationally， was discovered for the first time locally with an increasing proportion， accounting for 7.95% of all rotavirus positive cases. Phylogenic analysis demonstrated that the representative strains of this genotype were genetically closer to the DS-1-like G8P ［8］ strain found in Southeast Asia.

Conclusion The changes in the prevalence of various norovirus genotypes together with the emergence of rare rotavirus genotype in the local area illustrate the importance of continuous monitoring of viral diarrhea and genotyping of key pathogens. Increased local activity of the rare genotype also adds new parameters in the efficacy evaluation of marketed vaccines and development of potential new vaccines in near future.