Department of Epidemiology and Public Health, Sciensano, Brussels, Belgium
European Programme for Intervention Epidemiology Training (EPIET), ECDC, Solna, Sweden.
BMJ Open. 2021 Jun 29;11(6):e050824. doi: 10.1136/bmjopen-2021-050824.
To describe prevalence and incidence of anti-SARS-CoV-2 antibodies among Belgian hospital healthcare workers (HCW) in April-December 2020.
Prospective cohort study. Follow-up was originally planned until September and later extended.
Multicentre study, 17 hospitals.
50 HCW were randomly selected per hospital. HCW employed beyond the end of the study and whose profession involved contact with patients were eligible. 850 HCW entered the study in April-May 2020, 673 HCW (79%) attended the September visit and 308 (36%) the December visit.
A semiquantitative ELISA was used to detect IgG against SARS-CoV-2 in serum (Euroimmun) at 10 time points. In seropositive samples, neutralising antibodies were measured using a virus neutralisation test. Real-time reverse transcription PCR (RT-qPCR) was performed to detect SARS-CoV-2 on nasopharyngeal swabs. Participant characteristics and the presence of symptoms were collected via an online questionnaire.
Among all participants, 80% were women, 60% nurses and 21% physicians. Median age was 40 years. The seroprevalence remained relatively stable from April (7.7% (95% CI: 4.8% to 12.1%) to September (8.2% (95% CI: 5.7% to 11.6%)) and increased thereafter, reaching 19.7% (95% CI: 12.0% to 30.6%) in December 2020. 76 of 778 initially seronegative participants seroconverted during the follow-up (incidence: 205/1000 person-years). Among all seropositive individuals, 118/148 (80%) had a positive neutralisation test, 83/147 (56%) presented or reported a positive RT-qPCR, and 130/147 (88%) reported COVID-19-compatible symptoms at least once. However, only 46/73 (63%) of the seroconverters presented COVID-19-compatible symptoms in the month prior to seroconversion.
The seroprevalence among hospital HCW was slightly higher than that of the general Belgian population but followed a similar evolution, suggesting that infection prevention and control measures were effective and should be strictly maintained. After two SARS-CoV-2 waves, 80% of HCW remained seronegative, justifying their prioritisation in the vaccination strategy.
NCT04373889.
描述 2020 年 4 月至 12 月期间比利时医院医护人员（HCW）中抗 SARS-CoV-2 抗体的流行率和发病率。
前瞻性队列研究。最初计划随访至 9 月，后来延长。
多中心研究，17 家医院。
每家医院随机选择 50 名 HCW。在研究结束后仍受雇且其职业涉及与患者接触的 HCW 有资格参加。2020 年 4 月至 5 月期间，有 850 名 HCW 进入研究，673 名 HCW（79%）参加了 9 月的访问，308 名 HCW（36%）参加了 12 月的访问。
使用酶联免疫吸附试验（Euroimmun）在 10 个时间点检测血清中的 IgG 对 SARS-CoV-2 的反应（半定量）。在血清阳性样本中，使用病毒中和试验测量中和抗体。使用实时逆转录聚合酶链反应（RT-qPCR）检测鼻咽拭子中的 SARS-CoV-2。通过在线问卷收集参与者特征和症状存在情况。
在所有参与者中，80%为女性，60%为护士，21%为医生。中位年龄为 40 岁。血清阳性率从 4 月（7.7%（95%可信区间：4.8%至 12.1%）至 9 月（8.2%（95%可信区间：5.7%至 11.6%））相对稳定，此后增加，2020 年 12 月达到 19.7%（95%可信区间：12.0%至 30.6%）。在随访期间，778 名最初血清阴性的参与者中有 76 名发生血清转化（发病率：205/1000人年）。在所有血清阳性者中，118/148（80%）的中和试验阳性，83/147（56%）出现或报告 RT-qPCR 阳性，130/147（88%）至少出现过一次符合 COVID-19 的症状。然而，在血清转化前一个月，只有 46/73（63%）的血清转化者出现符合 COVID-19 的症状。
医院 HCW 的血清阳性率略高于比利时一般人群，但呈相似的演变，表明感染预防和控制措施是有效的，应严格维持。在经历了两次 SARS-CoV-2 浪潮后，80%的 HCW 仍呈血清阴性，这证明他们在疫苗接种策略中应优先考虑。
NCT04373889。
