Detection rates of norovirus gastroenteritis and factors associated with the infection before and during COVID-19 pandemic: a secondary analysis of surveillance data in Guangxi Zhuang Autonomous Region, Southern China.

Background: Changes in oral and hand hygiene behaviors have been reported during the COVID-19 pandemic in 2020 which may be associated with the incidence of the norovirus infection, a common cause of gastroenteritis. Objective: To estimate the trends of detection rates of norovirus gastroenteritis and associated factors before COVID-19 in 2015-2019 and during the COVID-19 in 2020 in Guangxi, China. Methods: A secondary analysis of Guangxi surveillance data of gastroenteritis patients was conducted. The detection rate in 2020 was predicted using an autoregressive integrated moving average modeland associated factors were analyzed using multiple logistic regression adjusted for interaction effects. Results: Of 7,903 gastroenteritis patients, the overall detection rate of norovirus gastroenteritis was 12.8%, (14.3% before and 6.1% during COVID-19). Detection rates gradually decreased from 2015 to 2020, of which the slope of predicted line was slightly flatter than the actual line. The odds ratios of detection were double to triple increase during COVID-19 in the younger age group and having food intake outside their homes. Tourist city, season, and types of food were independent associated factors. Conclusion: The detection rates were higher during the COVID-19 year among the population aged 45 years or less and those who consumed food outside their home.