Successful interruption of seasonal influenza transmission under the COVID-19 rapid response in Zhejiang Province, China

OBJECTIVES: The objective of this study was to evaluate whether the non-pharmaceutical interventions (NPIs) introduced to curb the spread of coronavirus disease 2019 (COVID-19) also interrupted the transmission of influenza. STUDY DESIGN: This is a descriptive epidemiological study. METHODS: Data on changes in the number of reported influenza cases, number of influenza-like illness (ILI) visits, ILI percentage and influenza virus positivity were compared between the first 18 weeks of 2020 and the same period of 2019. RESULTS: The changes in the weekly average number of influenza cases were statistically significant between 2020 and 2019 (−4319 vs −525 per week; P < 0.05). The slopes of regression lines for the number of ILI visits were also statistically significant between 2020 and 2019 (−911 vs −98 per week; P < 0.05). CONCLUSIONS: This study found that the prevalence of influenza was substantially decreased when NPIs were implemented for the containment of COVID-19.