Connolly Stephen P, Garcia Leon Alejandro, Green Sandra, McGee Daragh, Duggan Paul, Browne Robert, Miles Sarah, Negi Riya, Alalwan Dana, Natin Dominick, Mallon Patrick W, O'Gorman Peter, Lee Graham, Green David, McGinty Tara, Cotter Aoife G
Department of Infectious Diseases, Mater Misericordiae University Hospital, Dublin, Ireland.
School of Medicine, University College Dublin (UCD), Dublin, Ireland.
PLoS One. 2025 Jun 11;20(6):e0325544. doi: 10.1371/journal.pone.0325544. eCollection 2025.
Healthcare workers (HCWs) in Ireland bore a particularly high burden of SARS-CoV-2 infections, representing over 30% of infections during initial waves. We describe the prevalence, incidence and persistence of SARS-CoV-2 anti-nucleocapsid (anti-NC) IgG positivity in a cohort of HCWs working in a Dublin inner-city tertiary hospital, over 48 weeks.
The SORTeD (Seroprevalence, Seroconversion Rates and Transmission Dynamics of SARS-CoV-2 among Healthcare Workers) study was a longitudinal cohort study of HCWs working in an inner-city hospital in Dublin between July 2020 and September 2021. Participants had either a prior history of PCR-confirmed SARS-CoV-2 (Group 1) or no prior history of SARS-CoV-2 (Group 2). Serum samples were obtained at weeks 0, 12 and 48, and tested for SARS-CoV-2 nucleocapsid (NC) antibody using a qualitative immunoassay (Abbott Alinity®). Seroprevalence rates are presented using descriptive statistics, with univariate and multivariate analysis examining associations between participant characteristics, IgG status and refractive index in Group 1. Data is presented as n (%) or median (interquartile range (IQR)) where appropriate.
Of the 395 HCWs who were recruited, 304 (77.0%) were female, median age was 33 (28-45) years, and 343 (86.8%) had patient-facing roles. In Group 1, time from infection to sampling was 173 (144.0-202.0) days. Seroprevalence of IgG in Group 1 at 0, 12 and 48 weeks was 47.4%, 19.0% and 7.3%, respectively; while seroprevalence in Group 2 was 5.4%, 4.3% and 2.6%, respectively. A lower refractive index was seen in higher sampling intervals (r = -0.5, 95% CI -0.576 to -0.427; p < 0.001). Fourteen incident infections were reported by the cohort during the study, and 3 documented reinfections.
Our study shows low seroprevalence in prior confirmed cases among our HCW population, possibly explained by reduced sensitivity of this assay with increasing time from SARS-CoV-2 exposure and timing of testing. Confirmatory testing with a quantitative assay would help understand the true seroprevalence of SARS-CoV-2 IgG in this cohort.
爱尔兰的医护人员承受着特别高的新冠病毒感染负担，在最初几波疫情中，他们的感染病例占总数的30%以上。我们描述了都柏林市中心一家三级医院的医护人员队列中，48周内新冠病毒抗核衣壳（抗-NC）IgG阳性的患病率、发病率和持续情况。
SORTeD（医护人员中新冠病毒的血清流行率、血清转化率和传播动态）研究是一项对2020年7月至2021年9月期间在都柏林市中心一家医院工作的医护人员进行的纵向队列研究。参与者要么有PCR确诊的新冠病毒感染史（第1组），要么没有新冠病毒感染史（第2组）。在第0、12和48周采集血清样本，并使用定性免疫测定法（雅培Alinity®）检测新冠病毒核衣壳（NC）抗体。血清流行率用描述性统计数据表示，单因素和多因素分析用于检验第1组参与者特征、IgG状态和折光指数之间的关联。数据在适当情况下表示为n（%）或中位数（四分位间距（IQR））。
在招募的395名医护人员中，304名（77.0%）为女性，中位年龄为33岁（28 - 45岁），343名（86.8%）担任面向患者的工作。在第1组中，从感染到采样的时间为173天（144.0 - 202.0天）。第1组在第0、12和48周时IgG的血清流行率分别为47.4%、19.0%和7.3%；而第2组的血清流行率分别为5.4%、4.3%和2.6%。在较高的采样间隔中观察到较低的折光指数（r = -0.5，95%CI -0.576至 -0.427；p < 0.001）。该队列在研究期间报告了14例新发感染，3例有记录的再次感染。
我们的研究表明，在我们的医护人员群体中，先前确诊病例的血清流行率较低，这可能是由于随着距离接触新冠病毒时间的增加以及检测时间的推移，该检测方法的敏感性降低所致。使用定量检测进行确证性检测将有助于了解该队列中新冠病毒IgG的真实血清流行率。
