Abstract
Background
Quantifying antibody reactivity against multiple SARS-CoV-2 antigens may help understand individual differences in COVID-19 severity at the population level.
Methods
Cross-sectional study that included adults in the Vancouver area in British Columbia (BC), Canada, between May 17 and June 19, 2020. SARS-CoV-2 seroprevalence was ascertained by measuring total SARS-CoV-2 IgG/M/A against a recombinant spike (S1) protein and adjusted for bias due to false-positive and false-negative test results. A novel, high sensitivity multiplex assay was also used to profile IgG against four SARS-CoV-2 antigens, SARS-CoV and four circulating coronaviruses.
Findings
Among 276 participants (71% of health workers, HCW), three showed evidence of direct viral exposure, yielding an adjusted seroprevalence of 0.60% [95%CI 0% – 2.71%], with no difference between HCW and non-HCW, or between pediatric and adult HCW. Among the 273 unexposed individuals, 7.3% [95%CI 4.5% – 11.1%], 48.7 [95%CI 42.7% – 54.8%] and 82.4% [95%CI 77.4% – 86.7%] showed antibody reactivity against SARS-CoV-2 RBD, N or Spike, respectively. SARS-CoV-2 reactivity did not significantly correlate with age, sex, did not significantly differ between HCW and non-HCW (prevalence 1.0% vs 1.0%; P =1.00) and between pediatric and adult HCW (0.7% vs 1.6%; P =0.54), and modestly correlated with reactivity to circulating coronaviruses (Spearman rho range: 0.130 to 0.224 for 7 significant [FDR 5%], out of 16 of 36 correlations tested).
Interpretation
All individuals in this population displayed high antibody levels against common, circulating coronaviruses, and a substantial proportion of them showed low, but detectable antibody reactivity against SARS-CoV-2 antigens despite no evidence of direct SARS-CoV-2 exposure.
Funding
NIAID/NIH
Full Text Availability
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