kinetics of anti-SARS-CoV-2 antibodies over time. Results of 10 month follow up in over 300 seropositive Health Care Workers.

BACKGROUND: The kinetics of the antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) needs to be evaluated since long-term duration of antibody remains largely unknown, particularly in infected healthcare workers (HCW). METHODS: Prospective study, evaluating the longitudinal profile of anti-SARS-CoV-2 antibody titers in a random sample of 331 seropositive healthcare workers (HCW) of Spanish Hospitals Group. Serial measurements of serum IgG-anti-SARS-CoV-2 were obtained at baseline (April-May,2020), and in 2 follow-up visits. Linear mixed models were used to investigate antibody kinetics and associated factors. RESULTS: A total of 306 seropositive subjects (median age: 44.7years;69.9% female) were included in the final analysis. After a median follow-up of 274 days between baseline and final measurement, 235(76.8%) maintained seropositivity. Antibody titers decreased in 82.0%, while remained stable in 13.1%. Factors associated with stability of antibodies over time included age≥45 years, higher baseline titers, severe/moderate infection and high-grade exposure to COVID-19 patients. In declining profile, estimated mean antibody half-life was 146.3 days(95%CI:138.6-154.9) from baseline. Multivariate models show independent longer durability of antibodies in HCW with high-risk exposure to COVID-19 patients (+14.1 days;95%CI:0.6-40.2) and with symptomatic COVID-19 (+14.1 days;95%CI:0.9-43.0). The estimated mean time to loss antibodies was 375(95% CI:342-408) days from baseline. CONCLUSIONS: We present the first study measuring the kinetics of antibody response against SARS-CoV-2 in HCW beyond 6 months. Most participants remained seropositive after 9 months but presented a significant decline in antibody-titers. Two distinct antibody dynamic profiles were observed (declining vs. stable). Independent factors associated with longer durability of antibodies were symptomatic infection and higher exposure to COVID-19 patients.

Seroprevalence of SARS-CoV-2 antibodies in over 6000 healthcare workers in Spain.

BACKGROUND: Spain has one of the highest incidences of coronavirus disease 2019 (COVID-19) worldwide, so Spanish health care workers (HCW) are at high risk of exposure. Our objective was to determine severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody seroprevalence amongst HCW and factors associated with seropositivity. METHODS: A cross-sectional study evaluating 6190 workers (97.8% of the total workforce of a healthcare-system of 17 hospitals across four regions in Spain) was carried out between April and June 2020, by measuring immunoglobulin G (IgG)-SARS-CoV-2 antibody titres and related clinical data. Exposure risk was categorized as high (clinical environment; prolonged/direct contact with patients), moderate (clinical environment; non-intense/no patient contact) and low (non-clinical environment). RESULTS: A total of 6038 employees (mean age 43.8 years; 71% female) were included in the final analysis. A total of 662 (11.0%) were seropositive for IgG against SARS-CoV-2 (39.4% asymptomatic). Adding available PCR-testing, 713 (11.8%) employees showed evidence of previous SARS-CoV-2 infection. However, before antibody testing, 482 of them (67%) had no previous diagnosis of SARS-CoV-2-infection. Seroprevalence was higher in high- and moderate-risk exposure (12.1 and 11.4%, respectively) compared with low-grade risk subjects (7.2%), and in Madrid (13.8%) compared with Barcelona (7.6%) and Coruña (2.0%). High-risk [odds ratio (OR): 2.06; 95% confidence interval (CI): 1.63-2.62] and moderate-risk (OR: 1.77; 95% CI: 1.32-2.37) exposures were associated with positive IgG-SARS-CoV-2 antibodies after adjusting for region, age and sex. Higher antibody titres were observed in moderate-severe disease (median antibody-titre: 13.7 AU/mL) compared with mild (6.4 AU/mL) and asymptomatic (5.1 AU/mL) infection, and also in older (>60 years: 11.8 AU/mL) compared with younger (<30 years: 4.2 AU/mL) people. CONCLUSIONS: Seroprevalence of IgG-SARS-CoV-2 antibodies in HCW is a little higher than in the general population and varies depending on regional COVID-19 incidence. The high rates of subclinical and previously undiagnosed infection observed in this study reinforce the utility of antibody screening. An occupational risk for SARS-CoV-2 infection related to working in a clinical environment was demonstrated in this HCW cohort.

Infections by emerging serogroups of Neisseria meningitidis: A case report / Infecciones por serogrupos emergentes de Neisseria meningitidis: a propósito de un caso

No disponible