Work place and prevalence of COVID-19 in a rural population in Greece.

INTRODUCTION: Coronavirus disease-19 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic, giving rise to a serious global health threat. Many countries including Greece have seen a two-wave pattern of reported cases, with a first wave in spring and a second in autumn of 2020. METHODS: A cross-sectional seroprevalence study was designed to measure the prevalence of IgG antibodies with a quantitative SARS-CoV-2 IgG lab-based serology test, chemiluminescent microparticle immunoassay, against novel coronavirus in rural areas in Greece after the second pandemic wave. The study was conducted on 29 January 2021 in a rural semi-closed area, the municipality of Deskati, prefecture of western Macedonia in Greece after the second pandemic wave. RESULTS: Sixty-nine participants were included in this study. The present study demonstrated a high prevalence of COVID-19 infection (31 of 69 total participants; 45%) and those who were working in the public sector were at higher risk of COVID-19 infection in comparison to their counterparts in private sector (p=0.05364), (relative risk 2.64; 95% confidence interval 1.001-7.086). CONCLUSION: The study presents data showing a high prevalence of herd immunity for COVID-19 in a semi-closed area in Greece. These findings might help to understand the characteristics of this second wave, the behaviour and danger of SARS-CoV-2 in rural areas in Greece and Europe generally.

Do the Kinetics of Antibody Responses Predict Clinical Outcome in Hospitalized Patients With Moderate-to-Severe COVID-19?

BACKGROUND/AIM: The relationship between the kinetics of antibody responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the severity of Coronavirus Disease 2019 (COVID-19) is poorly understood. The aim of the present study was to investigate whether serum SARS-CoV-2 antibody kinetics serve as an early predictor of clinical deterioration or recovery in hospitalized patients with COVID-19. PATIENTS AND METHODS: In this prospective observational study, 102 consecutive patients (median age: 60 years, 58% males) with symptomatic COVID-19 infection diagnosed by real-time polymerase chain reaction assay, hospitalized in two tertiary hospitals, were included. Rapid test for qualitative detection of immunoglobulin M (IgM) and immunoglobulin G (IgG) SARS-CoV-2 antibodies was performed at pre-defined time intervals during hospitalization (days: 0, 3, 7, 10, 14, 21 and 28). RESULTS: During a 3-month follow-up period after COVID-19 disease onset, a total of 87 patients were discharged, 12 patients were intubated and entered the Intensive Care Unit, and three patients died. The median time for seroconversion was 10 days for IgM and 12 days for IgG post onset of symptoms. Univariate logistic regression analysis found no associations between IgM or IgG positivity and clinical outcomes or complications during hospitalization for COVID-19 infection. Diabetes and dyslipidemia were the only clinical risk factors predictive of COVID-19-related complications during hospitalization. CONCLUSION: SARS-CoV-2 antibody responses do not predict clinical outcome in hospitalized patients with moderate-to-severe COVID-19 infection.

Temporal Associations of the SARS-CoV-2 NP Antigen and Anti-Spike Total Ig Levels with Laboratory Parameters in a Greek Cohort of Hospitalized COVID-19 Patients.

Background: The direct effect of SARS-CoV-2 on the lungs results in increased hospitalization rates of patients with pneumonia. Severe COVID-19 patients often develop ARDS which is associated with poor prognosis. Assessing risk factors for COVID-19 severity is indispensable for implementing and evaluating therapeutic interventions. We investigated the temporal associations between the SARS-CoV-2 antigen (Ag), total Immunoglobulin (Ig) levels, and several laboratory parameters in hospitalized patients with varying degrees of COVID-19 severity. Methods: The SARS-CoV-2 nucleocapsid protein (NP) and total Ig Spike (S) protein-specific antibodies were determined for each patient with lateral flow assays through repeated sampling every two days. Hematological and biochemical parameters were evaluated at the same time points. Results: 40 Greek COVID-19 patients (31 males, 9 females) with a median age of 59.50 ± 16.21 years were enrolled in the study. The median time from symptom onset to hospitalization was 8.0 ± 4.19 days. A significant negative correlation was observed between the SARS-CoV-2 Ag and total Ig levels. The temporal correlation patterns of the SARS-CoV-2 NP Ag and anti-S total Ig levels with laboratory markers varied among patients with differing degrees of COVID-19 severity. Severe-critical cases had lower SARS-CoV-2 Ag and increased total Ig levels as compared to mild-moderate cases. Conclusions: Distinct temporal profiles of the SARS-CoV-2 NP Ag and anti-S total Ig levels may distinguish different groups of COVID-19 severity.

Understanding COVID-19 Epidemiology and Implications for Control: The Experience from a Greek Semi-Closed Community.

BACKGROUND: We aimed to estimate the SARS-CoV-2 antigen and antibody seroprevalence in one of the worst-affected by the pandemic semi-closed communities in Greece, Deskati, and evaluate the sociodemographic and clinical correlations of functional antibody responses. METHODS: The Ag2019n-CoV V1310/V1330 Rapid Test (Prognosis Biotech, Greece) was used for antigen detection. The Rapid Test 2019-nCoV Total Ig, V1210/V1230 (Prognosis Biotech, Greece), and the SARS-CoV-2 IgG II Quant method (Architect, Abbott, Illinois, USA) were used for antibody testing. RESULTS: None of the participants had a positive antigen result. SARS-CoV-2 seropositivity ranged from 13% to 45% in the study population, depending on the method. One-third of the participants with known past infection had a positive antibody test result 77 ± 13 days after infection. Two-fifths of infections determined by serology were asymptomatic. The advancing age and hospitalization predicted seropositivity among patients with past infection. Half of the participants who tested positive for antibodies were not aware of past infection. CONCLUSIONS: High-burden contexts in Greece, such as Deskati, are not so far from herd immunity thresholds. We highlighted the value of low-cost serosurveys targeting both symptomatic and asymptomatic populations to evaluate the natural immune response to SARS-CoV-2 in nonvaccinated susceptibles and design evidence-based policies for lifting lockdowns.