Infectious Diseases Section, Department of Diagnostics and Public Health, University of Verona, Verona, Italy.
School of Health Sciences, University of Brighton, Brighton, UK.
Epidemiol Infect. 2022 Feb 21;150:e48. doi: 10.1017/S0950268822000280.
SARS-CoV-2 serological tests are used to assess the infection seroprevalence within a population. This study aims at assessing potential biases in estimating infection prevalence amongst healthcare workers (HCWs) when different diagnostic criteria are considered. A multi-site cross-sectional study was carried out in April-September 2020 amongst 1.367 Italian HCWs. SARS-CoV-2 prevalence was assessed using three diagnostic criteria: RT-PCR on nasopharyngeal swab, point-of-care fingerprick serological test (POCT) result and COVID-19 clinical pathognomonic presentation. A logistic regression model was used to estimate the probability of POCT-positive result in relation to the time since infection (RT-PCR positivity). Among 1.367 HCWs, 69.2% were working in COVID-19 units. Statistically significant differences in age, role and gender were observed between COVID-19/non-COVID-19 units. Prevalence of SARS-CoV-2 infection varied according to the criterion considered: 6.7% for POCT, 8.1% for RT-PCR, 10.0% for either POCT or RT-PCR, 9.6% for infection pathognomonic clinical presentation and 17.6% when at least one of the previous criteria was present. The probability of POCT-positive result decreased by 1.1% every 10 days from the infection. This study highlights potential biases in estimating SARS-CoV-2 point-prevalence data according to the criteria used. Although informative on infection susceptibility and herd immunity level, POCT serological tests are not the best predictors of previous COVID-19 infections for public health monitoring programmes.
SARS-CoV-2 血清学检测用于评估人群中的感染血清流行率。本研究旨在评估在考虑不同诊断标准时，估计医护人员（HCWs）感染流行率时可能存在的偏差。2020 年 4 月至 9 月，在意大利进行了一项多地点横断面研究，共纳入 1367 名 HCWs。使用三种诊断标准评估 SARS-CoV-2 流行率：鼻咽拭子 RT-PCR、即时指尖血清学检测（POCT）结果和 COVID-19 临床特征。使用逻辑回归模型估计 POCT 阳性结果与感染后时间（RT-PCR 阳性）的关系。在 1367 名 HCWs 中，69.2%在 COVID-19 病房工作。COVID-19/非 COVID-19 病房之间观察到年龄、角色和性别存在统计学差异。根据所考虑的标准，SARS-CoV-2 感染的流行率不同：POCT 为 6.7%，RT-PCR 为 8.1%，POCT 或 RT-PCR 均为 10.0%，感染特征性临床表现为 9.6%，至少有一个之前标准存在时为 17.6%。从感染开始，每 10 天 POCT 阳性结果的概率降低 1.1%。本研究强调了根据使用的标准估计 SARS-CoV-2 时点流行率数据时可能存在的偏差。尽管 POCT 血清学检测对于感染易感性和群体免疫水平具有信息性，但对于公共卫生监测计划而言，它们并不是预测既往 COVID-19 感染的最佳指标。
