Seroprevalence of SARS-CoV-2 IgG Antibodies in Corsica (France), April and June 2020

Abstract

Our aim was to assess the seroprevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection after the lockdown in a sample of the Corsican population. Between 16 April and 15 June 2020, 2312 residual sera were collected from patients with a blood analysis conducted in one of the participating laboratories. Residual sera obtained from persons of all ages were tested for the presence of anti-SARS-CoV-2 Immunoglobulin G (IgG) using the EUROIMMUN enzyme immunoassay kit for semiquantitative detection of IgG antibodies against the S1 domain of viral spike protein (ELISA-S). Borderline and positive samples in ELISA-S were also tested with an in-house virus neutralization test (VNT). Prevalence values were adjusted for sex and age. A total of 1973 residual sera samples were included in the study. The overall seroprevalence based on ELISA-S was 5.27% (95% confidence interval (CI), 4.33–6.35) and 5.46% (4.51–6.57) after adjustment. Sex was not associated with IgG detection. However, significant differences were observed between age groups (p-value = 1 E-5). The highest values were observed among 10–19, 30–39, and 40–49 year-old age groups, ranging around 8–10%. The prevalence of neutralizing antibody titers ≥40 was 3% (2.28–3.84). In conclusion, the present study showed a low seroprevalence for COVID-19 in Corsica, a finding that is in accordance with values reported for other French regions in which the impact of the pandemic was low.

Nationwide Seroprevalence of SARS-CoV-2 IgG Antibodies among Four Groups of Primary Health-Care Workers and Their Household Contacts 6 Months after the Initiation of the COVID-19 Vaccination Campaign in France: SeroPRIM Study Protocol

“…The neutralization titer refers to the highest dilution of serum with a positive result. Specimens with a VNT titer ≥ 40 were considered positive in agreement with previous studies [17,18].…”

Impact of the Second Epidemic Wave of SARS-CoV-2: Increased Exposure of Young People

“…According to overall weighted seroprevalence observed in RS at mid-June ( 3 ) and at the end of October (clinical laboratory data) a minimum sample size of 1,109 was calculated assuming an a priori 7% anti-SARS-CoV-2 IgG seroprevalence (data estimated in November, 2020), a confidence in the estimate of 95%, a maximum allowable error in the prevalence of 1.5% and a Corsican population size of 344,679 habitants based on the latest French census data ( 8 , 10 ).…”

“…Our previous Corsica-based seroprevalence study estimated that in mid-June 5.46% of the Corsican population had been infected by SARS-CoV-2 ( 3 ). Consistent with previous population-based serosurveys ( 4 – 6 ), we reported noticeable age-related differences, with a lower seroprevalence in children <9 year-old compared with adolescents and adults.…”

“…UR 7310, Laboratoire de Virologie, Université de Corse, Corte, France, 2 Unité des Virus Émergents: Aix Marseille University, IRD 190, INSERM 1207, IHU Méditerranée Infection, Marseille, France, 3 Laboratoire de biologie médicale, CCF, Ajaccio, France, 4 Laboratoire de Biologie médicale 2A2B, Corte, France…”

Dramatic rise in seroprevalence rates of SARS-CoV-2 antibodies among healthy blood donors: The evolution of a pandemic

“…Numerous population seroprevalence studies have been conducted (Bajema et al, 2020;Lai et al, 2020;Chughtai et al, 2020;McLaughlin et al, 2020;Naranbhai et al, 2020;Sam et al, 2021;Sutton et al, 2020;Menachemi et al, 2020;Silveira et al, 2020;Kar et al, 2021;Vena et al, 2020;Pollán et al, 2020;Bogogiannidou et al, 2020;Poustchi et al, 2020;Ng et al, 2020;Figueiredo-Campos et al, 2020;Stringhini et al, 2020;Havers et al, 2020;Ho et al, 2020;Xu et al, 2020;Qutob et al, 2021;Capai et al, 2020;Sood et al, 2020;Godbout et al, 2020;Rostami et al, 2020) in efforts to estimate the true prevalence of COVID-19 infection.…”