Cost Effective Proactive Testing Strategies During COVID-19 Mass Vaccination: A Modelling Study

Background: As SARS-CoV-2 vaccines are administered worldwide, the COVID-19 pandemic continues to exact significant human and economic costs. Mass testing followed by isolation of positive cases can substantially mitigate risks and be tailored to local epidemiological conditions to ensure cost effectiveness. Methods: Using a multi-scale model that incorporates population-level SARS-CoV-2 transmission and individual-level viral load kinetics, we derive optimal SARS-CoV-2 proactive testing strategies in which the frequency of testing and duration of insolation depend on the local transmission rate and proportion immunized. Findings: Assuming a willingness-to-pay of US$100,000 per year of life lost (YLL) and a price of $5 per test, the optimal strategy under a rapid transmission scenario ( R e ~ 1.9) is weekly testing combined with a 10-day isolation period of positive cases and their households. Under a low transmission scenario ( R e ~ 1.2), the optimal sequence is weekly testing until the population reaches 10% immunity, followed by monthly testing until 30% immunity, and no testing thereafter. Interpretation: Mass proactive testing and case isolation is a cost effective strategy for mitigating the COVID-19 pandemic in the initial stages of the global SARS-CoV-2 vaccination campaign and in response to resurgences of vaccine-evasive variants. Funding: Financial support was provided by US National Institutes of Health (grant no. U01 GM087719 and K01 AI141576) and CDC COVID Supplement (grant no. U01P001136-01-01, CDC-HHS-6U01IP001137-01, and CDC-HHS 5U01IP0001137), the Health and Medical Research Fund, Food and Health Bureau, Government of the Hong Kong Special Administrative Region (grant no. COVID190118 and no. 20190712), European Research Council (grant no. 804744), and EPSRC Impact Acceleration Grant (grant no. RG90413). Declaration of Interest: We declare no competing interests.