Evaluation of prevention and control measures for a waterborne norovirus outbreak in Beijing based on dynamic model

  Objective  To characterize the transmission dynamics of an outbreak of acute gastroenteritis caused by a community-transmitted waterborne norovirus infection in a district in Beijing, and to evaluate the effectiveness of different prevention and control measures to explore the best prevention and control measures.

  Methods  Statistical description of cases in a norovirus outbreak in Beijing 2019, are carried out while the Susceptible-Exposed-Infectious/asymptomatic-Removed-Water/food (SEIARW) dynamic model is performed at the same time. the impact of prevention and control measures including blocking waterborne transmission, health education, and requiring patients to stay at home and prohibiting gatherings and other isolation related measures.

  Results  Without intervention, the effective reproduction number of norovirus in this outbreak was 9.32, the incidence rate could be 70.00%, and the duration of the outbreak was 45.26 days. The earlier water transmission is interrupted, the lower the incidence rate and the longer the duration of the epidemic. Health promotion measures can also lead to lower incidence rates and lower epidemic curves. Isolation-related measures could shorten the duration of the epidemic, and the higher the isolation rate, the lower the incidence rate, and the better the prevention and control effect of same-day measures than next-day measures.The best prevention and control effect can be achieved when measures to interrupt water transmission are taken on the day the outbreak is reported, along with health promotion and isolation on the day the outbreak is reported, and the isolation rate is 75.00%.

  Conclusion  The earlier the measures to interrupt water transmission, continuous health education and early isolation can be effective in controlling outbreaks to varying degrees.