Seroprevalence of Anti-SARS-CoV-2 Antibodies in a Random Sample of Inhabitants of the Katowice Region, Poland.

Jan E Zejda,Małgorzata Kowalska,Paweł Buszman,Grzegorz M Brożek,Kamil Barański,Artur Nowakowski,Angelina Kaleta-Pilarska,Yuchen Xia

doi:10.3390/ijerph18063188

Abstract

Lack of knowledge around seroprevalence levels of COVID-19 in Poland was the reason for the implementation of a seroepidemiological study in the Katowice Region (2,100,000 inhabitants). In October–November 2020, a questionnaire examination and measurement of anti-SARS-CoV-2 IgG and IgM antibodies were performed in a random sample of the general population (n = 1167). The objectives of the study were to estimate the prevalence of IgG and IgM antibodies and to assess their host-related correlates. The prevalence of IgG seropositivity was 11.4% (95% CI: 9.5–13.2%) and IgM seropositivity was 4.6% (95% CI: 3.5–5.8%). Diagnosis of COVID-19 was found in 4.8% of subjects. A positive IgG test was statistically significantly associated with age (inverse relationship), a person’s contact with a COVID-19 patient, quarantine, and two symptoms in the past: fever and loss of smell/taste. Positive IgG tests were less prevalent in subjects who had diagnoses of arterial hypertension, diabetes, or rheumatologic disorders. IgM test positivity was associated with quarantine and loss of smell/taste only with no effect of chronic diseases found. In Poland, in the period October–November 2020, the prevalence of SARS-CoV-2 infection was larger than earlier estimates obtained in other European countries, probably reflecting the measurements obtained during the “second wave” of the epidemic.

Highlights

In Poland, the first confirmed case of COVID-19 was reported at the beginning of March 2020
The product data sheet of the SARS-CoV-2 ELISA used in our study shows 94.4% sensitivity (10 days after symptom onset) and 99.6% specificity of the IgG test and 88.2% sensitivity
Female subjects did not differ in COVID-19 related history but they had more frequent nonspecific symptoms suggestive of a viral infection

Summary

Introduction

In Poland (pop. 37,672,367), the first confirmed case of COVID-19 was reported at the beginning of March 2020. Up to 29 January 2021, the cumulative number of SARS-CoV-2 infections has reached 1,502,810 cases, including 36,780 deaths. Return of partial lock-down regulations took place in October and have been in effect since . This flow of events parallels the changing epidemiology of COVID-19 in Poland. In the period between March–September, the daily number of reported SARS-CoV-2 infections increased from approximately 300 at the end of June to 500–600 in mid-September, and to the daily maximum of 27,875 in November. From the start of the pandemic until September, COVID-19 mortality usually did not exceed 30 deaths/day, and sharply increased reaching 500–600 per day in November and December [1]

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