High seroprevalence but short‐lived immune response to SARS‐CoV‐2 infection in Paris

Abstract

Although the COVID‐19 pandemic peaked in March/April 2020 in France, the prevalence of infection is barely known. Using high‐throughput methods, we assessed herein the serological response against the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) of 1847 participants working in three sites of an institution in Paris conurbation. In May–July 2020, 11% (95% confidence interval [CI]: 9.7–12.6) of serums were positive for IgG against the SARS‐CoV‐2 N and S proteins, and 9.5% (95% CI: 8.2–11.0) were neutralizer in pseudo‐typed virus assays. The prevalence of seroconversion was 11.6% (95% CI: 10.2–13.2) when considering positivity in at least one assay. In 5% of RT‐qPCR positive individuals, no systemic IgGs were detected. Among immune individuals, 21% had been asymptomatic. Anosmia (loss of smell) and ageusia (loss of taste) occurred in 52% of the IgG‐positive individuals and in 3% of the negative ones. In contrast, 30% of the anosmia–ageusia cases were seronegative, suggesting that the true prevalence of infection may have reached 16.6%. In sera obtained 4–8 weeks after the first sampling, anti‐N and anti‐S IgG titers and neutralization activity in pseudo‐virus assay declined by 31%, 17%, and 53%, resulting thus in half‐life of 35, 87, and 28 days, respectively. The population studied is representative of active workers in Paris. The short lifespan of the serological systemic responses suggests an underestimation of the true prevalence of infection.

Epidemiological feature, viral shedding, and antibody seroconversion among asymptomatic SARS-CoV-2 carriers and symptomatic/presymptomatic COVID-19 patients

“…This was also observed in Importantly, seroconversion of IgG against SARS-CoV-2 from positive to negative or weak positive occurred 53.4% in asymptomatic carriers and 25.5% in COVID-19 patients ( P =0.059), while consistently seropositive rate of IgG against SARS-CoV-2 was significantly higher in COVID-19 patients than in asymptomatic carriers ( P =0.037). The similar observations concerning rapid seroconversion of the antibody against SARS-CoV-2 or short-lived immune response after mild infection were also reported in the frontline health care personnel in the US and active workers in France [23, 24]. These data indicate that humoral immunity against SARS-CoV-2 was not efficiently aroused by a relative short exposure of SARS-CoV-2 in asymptomatic carriers or in those with a stronger innate and cell immunity.…”

Epidemiological feature, viral shedding, and antibody seroconversion among asymptomatic SARS-CoV-2 carriers and symptomatic/ presymptomatic COVID-19 patients

“…Importantly, seroconversion of IgG against SARS-CoV-2 from positive to negative or weak positive occurred 53.4% in asymptomatic carriers and 25.5% in COVID-19 patients (P = 0.059), while consistently seropositive rate of IgG against SARS-CoV-2 was signi cantly higher in COVID-19 patients than in asymptomatic carriers (P = 0.037). The similar observations concerning rapid seroconversion of the antibody against SARS-CoV-2 or short-lived immune response after mild infection were also reported in the frontline health care personnel in the US and active workers in France [22,23]. These data indicate that humoral immunity against SARS-CoV-2 was not e ciently aroused by a relative short exposure of SARS-CoV-2 in asymptomatic carriers or in those with a stronger innate and cell immunity.…”

Prevalence of SARS-CoV-2 antibodies in France: results from nationwide serological surveillance

“…Several studies similarly reported that only a fraction of seropositive individuals had detectable levels of neutralising antibodies, this fraction being variable 2 , 3 , 7 – 9 . This finding could be explained by differences in antibody kinetics with delayed appearance of neutralising antibodies 20 .…”