Retrospective SARS‐CoV‐2 IgG screening during the first wave (March–June 2020) of the COVID‐19 pandemic in the United Kingdom

Bird, Paul William; Sandhu, Kyran; Fletcher, Oliver; Ames, Billy; Toovey, Oliver; Tang, Julian Wei‐Tze

During the “first wave” of the coronavirus disease 2019 (COVID‐19) pandemic in the United Kingdom (March–June 2020), the city of Leicester was particularly hard hit, resulting in reimposed lockdown measures. Although initial polymerase chain reaction testing for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) was attempted within the community, testing was soon abandoned due to an inability to keep up with demand by local laboratories. It is therefore feasible that undiagnosed transmission of COVID‐19 in the community by asymptomatic individuals was a real possibility. Therefore, retrospective SARS‐CoV‐2 immunoglobulin G (IgG) testing of archived sera from out‐patients visiting University Hospitals of Leicester NHS Trust service was performed to investigate the transmission of SARS‐CoV‐2 in the community. A total of 1779 sera samples were tested from samples collected between 16th March and 3rd June 2020, of which 202 (11.35%) were SARS‐CoV‐2 IgG positive. Positivity was lowest in March (2.54%) at the beginning of the pandemic before peaking in April (17.16%) before a decline in May and June (11.16% and 12.68%, respectively). This retrospective screening offers some insight into the early patterns of SARS‐CoV‐2 transmission within a sampled community population during the first wave of the COVID‐19 pandemic; supporting the argument for more community screening during high incidences of pandemics.