Estimates of the rate of infection and asymptomatic COVID-19 disease in a population sample from SE England

• DOI: 10.1016/j.jinf.2020.10.011
• Publication Date: 2020-10-15T07:21:27Z
• Authors: Philippa M. Wells; Katie J. Doores; Simon Couvreur; Rocio Martinez Nunez; Jeffrey Seow; Carl Graham; Sam Acors; Neophytos Kouphou; Stuart J.D. Neil; Richard S. Tedder; Pedro M. Matos; Kate Poulton; Maria Jose Lista; Ruth E. Dickenson; Helin Sertkaya; Thomas J.A. Maguire; Edward J. Scourfield; Ruth C.E. Bowyer; Deborah Hart; Aoife O'Byrne; Kathryn J.A. Steel; Oliver Hemmings; Carolina Rosadas; Myra O. McClure; Joan Capedevilla-...; Jonathan Wolf; Sebastien Ourselin; Matthew A. Brown; Michael H. Malim; Tim Spector; Claire J. Steves
• Keywords: Microbiology (medical); Adult; Male; Anosmia; Population; Twins; 610; Enzyme-Linked Immunosorbent Assay; 613; Antibodies, Viral; Article; 03 medical and health sciences; 0302 clinical medicine; Seroepidemiologic Studies; Humans; UK; Prospective Studies; Asymptomatic Infections; Antibody; Aged; Aged, 80 and over; SARS-CoV-2; Immunity; COVID-19; Middle Aged; Asymptomatic; 3. Good health; Infectious Diseases; England; Immunoglobulin M; Immunoglobulin G; Spike Glycoprotein, Coronavirus; Female; Seropoprevalence

AbstractBackgroundUnderstanding of the true asymptomatic rate of infection of SARS-CoV-2 is currently limited, as is understanding of the population-based seroprevalence after the first wave of COVID-19 within the UK. The majority of data thus far come from hospitalised patients, with little focus on general population cases, or their symptoms.MethodsWe undertook enzyme linked immunosorbent assay characterisation of IgM and IgG responses against SARS-CoV-2 spike glycoprotein and nucleocapsid protein of 431 unselected general-population participants of the TwinsUK cohort from South-East England, aged 19-86 (median age 48; 85% female). 382 participants completed prospective logging of 14 COVID-19 related symptoms via the COVID Symptom Study App, allowing consideration of serology alongside individual symptoms, and a predictive algorithm for estimated COVID-19 previously modelled on PCR positive individuals from a dataset of over 2 million.FindingsWe demonstrated a seroprevalence of 12% (51participants of 431). Of 48 seropositive individuals with full symptom data, nine (19%) were fully asymptomatic, and 16 (27%) were asymptomatic for core COVID-19 symptoms: fever, cough or anosmia. Specificity of anosmia for seropositivity was 95%, compared to 88% for fever cough and anosmia combined. 34 individuals in the cohort were predicted to be Covid-19 positive using the App algorithm, and of those, 18 (52%) were seropositive.InterpretationSeroprevalence amongst adults from London and South-East England was 12%, and 19% of seropositive individuals with prospective symptom logging were fully asymptomatic throughout the study. Anosmia demonstrated the highest symptom specificity for SARS-CoV-2 antibody response.FundingNIHR BRC, CDRF, ZOE global LTD, RST-UKRI/MRC