The impact of surgical mask-wearing, contact tracing program, and vaccination on COVID-19 transmission in Taiwan from January 2020 to March 2022: a modelling study

The effectiveness of interventions such as public mask-wearing, contact tracing, and vaccination presents an important lesson for control of the further COVID-19 outbreaks without of whole country lockdowns and the restriction of individual movement. We simulated different scenarios of COVID-19 waves in Taiwan from 2020 to the beginning of March 2022 and considered the following interventions: travel restrictions, quarantine of infected individuals, contact tracing, mask-wearing, vaccination, and mass gathering restrictions. We propose an epidemiological compartmental model modified from the susceptible-exposed-infectious-removed (SEIR) model and derive a formula for the basic reproduction number (R) describing its dependence on all investigated parameters. The simulation results are fitted with the official Taiwanese COVID-19 data. Thus, the results demonstrate that the fast introduction of the interventions and maintaining them at a high level are able the outbreak control without strict lockdowns. By estimation of the R, it was shown that it is necessary to maintain on high implementation level of both non- and pharmaceutical intervention types to control the COVID-19 transmission. Our results can be useful as advice or recommendation for public health policies, and our model can be applied for other epidemiological simulation studies. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was funded by the National Health Research Institutes, Taiwan, grant number BN-109-PP-08, and the Ministry of Science and Technology, Taiwan, grant number MOST 106 2115 M 400 001. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present work are contained in the manuscript