SARS-CoV-2 antibody seroprevalence rates among Egyptian blood donors around the third wave: Cross-sectional study.

Abstract

BackgroundSeroprevalence studies may provide a more representative situation of the disease burden and population‐level immunity in a country.AimThe aim of this study was to determine the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) antibodies among asymptomatic blood donors attending the Cairo University blood bank services at various points in time around the third wave.MethodsThis cross‐section study included 3058 eligible blood donors, representing a demographically and socially heterogeneous healthy population and categorized as: Group 1, 954 donors in the period from March 20 to 30/2021; Group 2, 990 donors in the period from June 3 to 10/2021. These two groups were tested for IgG against SARS‐CoV‐2 nucleocapsid antigen (NC) to detect qualitative reactivity. Group 3, 1114 donors in the period from July 20 to 30/2021 were tested by the SARS‐CoV‐2 IgG II Quant assay for the quantitative detection of IgG antibodies, including neutralizing antibodies (antispike antibodies).ResultsDonors' age ranged between 18 and 59 (mean 33.9 ± 9) years. There was no significant correlation between seroprevalence and gender, area of residence, ABO or Rh blood types, and occupation or education. Antibody prevalence was found to be 13.2% in Group 1, 19.2% in Group 2 (overall 16.2%), and 66% in Group 3. There were only 49 included cases vaccinated against COVID‐19.ConclusionWe concluded that the significant increasing trend in seroprevalence rates during the third wave, March, June, and July, in Egypt, reflects a high cumulative incidence of seroconversion that mirrored the epidemic curve in its rise, fall, and nadir.