Enhanced surveillance of COVID-19 in Scotland: population-based seroprevalence surveillance for SARS-CoV-2 during the first wave of the epidemic

The impact of the COVID-19 pandemic in Scotland has been amongst most severe Europe. Serological surveillance is critical to determine overall extent infection across populations and inform public health response. This study aimed estimate proportion people who have antibodies SARS-CoV-2 (‘seroprevalence’) general population see if this changes over time. Between International Organization for Standardization (ISO) week 17 (i.e. commencing 20th April) ISO 25 (week 15 June), 4751 residual blood samples were obtained from regional biochemistry laboratories six participating authority areas covering approximately 75% Scottish population. Samples tested presence anti-SARS-CoV-2 IgG using LIAISON®SARS-CoV-2 S1/S2 assay (DiaSorin, Italy). Seroprevalence rates adjusted sensitivity specificity Bayesian methods. combined seroprevalence period was 4.3% (95% confidence interval: 4.2%–4.5%). varied each between 1.9% 6.8% with no difference antibody positivity by age, sex or geographical area. At end first wave pandemic, only a small fraction had SARS-CoV-2. Control requires ability detect asymptomatic mild infections that would otherwise remain undetected through existing systems. important true number within which, turn, can help understand transmission, control measures provide denominator estimation severity such as infected hospitalised and/or died.