Pandemic Preparedness Through Optimal Social Distancing: Guidelines for Assessing the Health/Economic Dilemmas

Background & aims of study: The COVID-19 pandemic has shown that social distancing remains the most important mitigation measure against severe epidemic threats until an effective vaccine is available. A key research area in COVID-19 is the design of optimal social distancing interventions in the integrated modelling context i.e., considering a range of dimensions including direct epidemiological costs as well as societal and economic costs. The aim of this work is to provide a background for future pandemic preparedness plans by comparing and testing the robustness of the time evolution of finite horizon optimal social distancing policies aimed at controlling an outbreak of a major infectious disease prior to the arrival of an effective vaccine with respect to different modelling options. Methods & results: Based on a diffusion model from established COVID-19 literature including finite public health resources, we provide a detailed investigation of optimal social distancing interventions balancing direct epidemiological costs with indirect societal costs of control measures. In particular, we focus on the dependence of the optimal intervention and the resulting epidemic burden on three key factors: (i) the degree of prioritization of indirect costs, (ii) the effectiveness of social distancing i.e., the adherence of the population to the measures, (iii) the timeliness of the intervention. We then extend the baseline model to a range of real-world scenarios, such as the presence of a constant inflow of silent infective travellers, non-exponentially distributed durations of the main epidemiological transitions, and different options between health and non-health dimensions of the cost function. Implications: To the best of our knowledge, this is the first effort to comprehensively assess the joint role of the decision makers’ preference for indirect costs – essentially reflecting the preference for epidemic suppression vs mitigation – and adherence to measures. Agreement on the prioritizing of direct costs and achieving high levels of adherence to proposed measures under a timeliness intervention are key to mitigating also of the indirect pandemic impact. Our work is a step towards creating a catalogue of social distancing strategies to be used as guidelines for future preparedness plans, applicable to a wide range of epidemic conditions.