Seroprevalence of Antibodies against SARS-CoV-2 among the Personnel and Students of the National and Kapodistrian University of Athens, Greece: A Preliminary Report

Abstract

Due to early implementation of public health measures, Greece had low number of SARS-CoV-2 infections and COVID-19 severe incidents in hospitalized patients. The National and Kapodistrian University of Athens (ΝΚUA), especially its health-care/medical personnel, has been actively involved in the first line of state responses to COVID-19. To estimate the prevalence of antibodies (Igs) against SARS-CoV-2 among NKUA members, we designed a five consecutive monthly serosurvey among randomly selected NKUA consenting volunteers. Here, we present the results from the first 2500 plasma samples collected during June–July 2020. Twenty-five donors were tested positive for anti-SARS-CoV-2 Igs; thus, the overall seroprevalence was 1.00%. The weighted overall seroprevalence was 0.93% (95% CI: 0.27, 2.09) and varied between males [1.05% (95% CI: 0.18, 2.92)] and females [0.84% (95% CI: 0.13, 2.49)], age-groups and different categories (higher in participants from the School of Health Sciences and in scientific affiliates/faculty members/laboratory assistants), but no statistical differences were detected. Although focused on the specific population of NKUA members, our study shows that the prevalence of anti-SARS-CoV-2 Igs for the period June–July 2020 remained low and provides knowledge of public health importance for the NKUA members. Given that approximately one in three infections was asymptomatic, continuous monitoring of the progression of the pandemic by assessing Ig seroprevalence is needed.

SARS-CoV-2 Infection Is Asymptomatic in Nearly Half of Adults with Robust Anti-Spike Protein Receptor-Binding Domain Antibody Response

“…Retesting of 988 participants, after 3 months, i.e., during October and November 2020, revealed an overall seroconversion incidence rate of 3.40 new cases per 100 person-years, which was higher than the seroprevalence estimated for the previous months. In our interim analysis, the weighted seroprevalence for volunteers tested until July 2020 was 0.93% [ 13 ].…”

“…Peripheral blood was collected, treated, and stored, as previously described [ 13 ]. Briefly, after venipuncture, blood was transferred to K2EDTA vacutainers (BD Biosciences, San Jose, CA, USA) and centrifuged at 500× g for 20 min within 3 h from collection.…”

Evaluation of four commercial, fully automated SARS-CoV-2 antibody tests suggests a revision of the Siemens SARS-CoV-2 IgG assay

“…SARS-CoV-2 seroprevalence is still used as a measure to estimate the true number of affected people during the pandemic. Such studies found seropositivity for SARS-CoV-2 antibodies in 2.4% (n=61,437) of residents in Wuhan in mid-May (34), 0.9% (n=3,186) in German regular blood donors from March to June (35), 1.0% (n=2,500) in Greece university personnel and students during June-July (36), and 4.6% (n=5,933) of health care workers till end of May at the University-Hospitals of Padova and Verona, Italy (31). Thus, a very high diagnostic specificity of serologic tests is crucial to minimize false positive results and improve the positive predictive value (PPV).…”

The Seroprevalence of SARS-CoV-2 in Europe: A Systematic Review

“…Six studies investigated the seroprevalence in school/university settings or among children only, across 5 different countries (41,55,60,105,110,125). Four of the studies examined the seroprevalence in schools (41,55,105,125).…”