Cost-effectiveness of whole area testing of asymptomatic SARS-CoV-2 infections in Merthyr Tydfil, 2020: A Modelling and economic analysis

Objectives: To evaluate the cost effectiveness of an asymptomatic SARS-CoV-2 whole area testing pilot. Design: Epidemiological modelling and cost effectiveness analysis. Setting: The community of Merthyr Tydfil County Borough between20 Nov and 21 Dec 2020. Participants: A total of 33,822 people tested as part of the pilot in Merthyr Tydfil County Borough, 712 of whom tested positive by lateral flow test and reported being asymptomatic. Main outcome measures: Estimated number of cases, hospitalisations, ICU admissions and deaths prevented, and associated costs per quality-adjusted life years (QALYs) gained and monitory cost to the healthcare system. Results: An initial conservative estimate of 360 (95% CI: 311 - 418) cases were prevented by the mass testing, representing a would-be reduction of 11% of all cases diagnosed in Merthyr Tydfil residents during the same period. Modelling healthcare burden estimates that 24 (16 - 36) hospitalizations, 5 (3 - 6) ICU admissions and 15 (11 - 20) deaths were prevented, representing 6.37%, 11.1% and 8.19%, respectively of the actual counts during the same period. A less conservative, best-case scenario predicts a much higher number of cases prevented of 2328 (1761 - 3107), representing 80% reduction in would-be cases. Cost effectiveness analysis indicates 108 (80 - 143) QALYs gained, an incremental cost ratio of £ 2,143 (£ 860-£ 4,175) per QALY gained and net monetary benefit of £ 6.2m (£ 4.5m-£ 8.4m). In the less conservative scenario, the net monetary benefit increases to £ 15.9m (£ 12.3m-£ 20.5m). Conclusions: A significant number of cases, hospitalisations and deaths were prevented by the mass testing pilot. Considering QALYs lost and healthcare costs avoided, the pilot was cost-effective. These findings suggest mass testing with LFDs in areas of high prevalence (>2%) is likely to provide significant public health benefit. It is not yet clear whether similar benefits will be obtained in low prevalence settings.