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

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.

SARS-CoV-2 Seroprevalence and Neutralizing Antibody Response after the First and Second COVID-19 Pandemic Wave in Croatia

“…In Germany (April–June 2020), seropositivity was 0.97% using ELISA, and 0.36% using VNT [ 20 ]. Significantly higher seropositivity was observed after the second pandemic peak, varying from 11.4% in Poland (October–November 2020) [ 21 ], and 19.3% in Spain (Madrid, at the end of 2020) [ 22 ], to 21.1% in Switzerland (Geneva, November–December 2020) [ 23 ]. In Slovenia, the seroprevalence after the first (April 2020) and second (October–November 2020) waves was found to be 2.78% and 4.06%, respectively [ 24 ].…”

Association between Influenza Vaccination and Positive SARS-CoV-2 IgG and IgM Tests in the General Population of Katowice Region, Poland

“…Moreover, obesity and diabetes were statistically significant risk factors for COVID-19-related mortality in this study. From an epidemiological point of view, it is important that the immune response to SARS-CoV-2 infection is heterogeneous and varies between individuals based on age, environment, and underlying health conditions [ 16 , 29 , 30 , 31 ]. The individual profile of the immune response is pertinent in shaping the risk of infection.…”

“…Ultimately, we introduced a supplementary recruitment in which we obtained 4312 spontaneous applicated residents of the selected cities (74.1% of the 5815 people willing to be tested for antibodies). The final group included 5479 residents (91.3% of the assumed number of people); age and sex distribution of the study group did not differ from the distribution in the general population of the Silesian Voivodeship [ 16 ] ( Supplementary Figure S1 ).…”

Impact of Two Different Recruitment Procedures (Random vs. Volunteer Selection) on the Results of Seroepidemiological Study (SARS-CoV-2)

“…In autumn 2020, the cross-sectional study assessing the seroprevalence of the SARS-CoV-2 virus was conducted in three Polish cities located in the Silesian Voivodeship (Gliwice, Katowice, and Sosnowiec). The methodology of this study and some of the results have already been presented and discussed in our previous articles [ 12 , 13 ]. The main research tools were questionnaires and measurement of anti-SARS-CoV-2 immunoglobulins (IgG and IgM).…”

“…The IgG seropositivity of asymptomatic healthcare workers from southern Poland varied between 1.2% and 10% (July/August 2020) [ 11 ]. In our recent seroepidemiological study on SARS-CoV-2 infection, we examined randomly selected subjects using questionnaires and immunological tests [ 12 ]. Our project also made possible applying the same research tools in a large group of volunteers, recruited from the same study area and examined in the same study period.…”