Mathematical modeling of the SARS-CoV-2 epidemic in Qatar and its impact on the national response to COVID-19

<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>Mathematical modeling constitutes an important tool for planning robust responses to epidemics. This study was conducted to guide the Qatari national response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic. The study investigated the time course of the epidemic, forecasted healthcare needs, predicted the impact of social and physical distancing restrictions, and rationalized and justified easing of restrictions.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>An age-structured deterministic model was constructed to describe SARS-CoV-2 transmission dynamics and disease progression throughout the population.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>The enforced social and physical distancing interventions flattened the epidemic curve, reducing the peaks for incidence, prevalence, acute-care hospitalization, and intensive care unit (ICU) hospitalizations by 87%, 86%, 76%, and 78%, respectively. The daily number of new infections was predicted to peak at 12,750 on May 23, and active-infection prevalence was predicted to peak at 3.2% on May 25. Daily acute-care and ICU-care hospital admissions and occupancy were forecast accurately and precisely. By October 15, 2020, the basic reproduction number <jats:italic>R</jats:italic><jats:sub>0</jats:sub> had varied between 1.07-2.78, and 50.8% of the population were estimated to have been infected (1.43 million infections). The proportion of actual infections diagnosed was estimated at 11.6%. Applying the concept of <jats:italic>R</jats:italic><jats:sub><jats:italic>t</jats:italic></jats:sub> tuning, gradual easing of restrictions was rationalized and justified to start on June 15, 2020, when <jats:italic>R</jats:italic><jats:sub><jats:italic>t</jats:italic></jats:sub> declined to 0.7, to buffer the increased interpersonal contact with easing of restrictions and to minimize the risk of a second wave. No second wave has materialized as of October 15, 2020, five months after the epidemic peak.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>Use of modeling and forecasting to guide the national response proved to be a successful strategy, reducing the toll of the epidemic to a manageable level for the healthcare system.</jats:p></jats:sec>