BACKGROUND: In response to the coronavirus disease 2019 (COVID-19) pandemic, many countries have implemented mitigating non-pharmaceutical interventions. We investigated the impact of these interventions and changes in public behavior on the incidences of selected vaccine-preventable diseases (VPDs) during the COVID-19 pandemic in the eastern of China. METHODS: From routine monitoring data collected in the capital of eastern China's Jiangsu Province, we extracted and analyzed the incidences of influenza; hand, foot and mouth disease (HFMD); varicella; mumps; pertussis; and hepatitis B. We also investigated the changes in public behavior during the COVID-19 pandemic through telephone interviews and questionnaire surveys. RESULTS: Compared with the baseline (2017-2019), the incidences of all VPDs except influenza declined significantly in 2020 (HFMD decreased by 79.92%, varicella decreased by 7.71%, mumps decreased by 2.03%, pertussis decreased by 78.91%, and hepatitis B decreased by 0.31%). The reduction in reported cases in children (0-14 years) was greater than that in adults, and pertussis had the largest reduction (approximately 80%) in children. Influenza peaks in winter; in the three years before the COVID-19 pandemic, Influenza rates took an average of 10 weeks to recede to their lowest levels after the Spring Festival, while in 2020, this took only 1 week. A total of 366 outbreaks with 20,205 cases were reported during the COVID-19 pandemic. Among the participants in the study, 94.2% of the interviewees avoided going to high-risk areas, 82.4% avoided going to crowded places, 92.9% wore masks when going out,88.4% washed their hands frequently, and 67.9% maintained social distance. CONCLUSIONS: Our study showed significant reductions in the incidences of VPDs after the implementation of a series of non-pharmaceutical interventions during the COVID-19 pandemic.