The Defense of Shangri-La: A Thought Experiment of Periodic Community-wide Screening in the Future Pandemic

Objectives In a dangerous future pandemic without effective vaccines and medicines, a reliable screening-and-isolation strategy can be the last opportunity to keep critical facilities and communities running and avoid a complete shutdown. Methods In this study, we introduced an epidemiological model that included essential parameters of infection transmission and screening. With varying parameters, we studied the dynamics of viral infection in the semi-isolated communities. Results In the scenario with a periodic infection screening once per 3 days and a viral basic reproduction number 3.0, more than 85% of the infection waves have a duration less than 7 days and the infection size in each of the waves is generally less than 4 individuals when the efficiency of infection discovery is 0.9 in the screening. When the period of screening was elongated to once per 7 days, the cases of infection dramatically increased to 5 folds of that mentioned previously. Further, with a weak discovery efficiency of 0.7 and the aforementioned low screening frequency, the spread of infection would be out of control. Conclusions Our study suggests that frequent periodic screening is capable of controlling a future epidemic in a semi-isolated community without vaccines and medicines.