Policlinico Riuniti Foggia Hospital, Hygiene Unit, Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy.
Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.
Biomed Res Int. 2022 Jan 6;2022:3401566. doi: 10.1155/2022/3401566. eCollection 2022.
Early in the COVID-19 pandemic, asymptomatic transmission represented an important challenge for controlling the spread of SARS-CoV-2 through the traditional public health strategies. Further understanding of the contribution of asymptomatic infections to SARS-CoV-2 transmission has been of crucial importance for pandemic control. We conducted a retrospective epidemiological study to characterize asymptomatic COVID-19 cases occurred in the Apulia region, Italy, during the first epidemic wave of COVID-19 outbreak (February 29-July 7, 2020). We analyzed data collected in a regional platform developed to manage surveillance activities, namely, investigation and follow-up of cases and contacts, contact tracing, and laboratory and clinical data collection. We included all asymptomatic cases that were laboratory-confirmed during the appropriate follow-up, defined as persons infected with SARS-CoV-2 who did not develop symptoms/clinical signs of the disease. Between February 29 and July 7, 2020, a total of 4,536 cases were diagnosed with COVID-19 among 193,757 tests performed. The group of persons with asymptomatic SARS-CoV-2 infection consisted of 903 cases; the asymptomatic proportion was 19.9% (95% CI: 18.8-21.1%); this decreased with increasing age (OR: 0.89, 95% CI: 0.83-0.96; = 0.001), in individuals with underlying comorbidities (OR: 0.55, 95% CI: 0.41-0.73; < 0.001), and in males (OR: 0.69, 95% CI: 0.54-0.87; = 0.002). The median asymptomatic SARS-CoV-2 RNA positive period was 19 days (IQR: 14-31) and the cumulative proportion of persons with resolution of infection 14 days after the first positive PCR test was 74%. As the public health community is debating the question of whether asymptomatic and late spreaders could sustain virus transmission in the communities, such cases present unique opportunities to gain insight into SARS-CoV-2 adaptation to human host. This has important implications for future COVID-19 surveillance and prevention.
在 COVID-19 大流行早期，无症状传播是通过传统公共卫生策略控制 SARS-CoV-2 传播的一个重要挑战。进一步了解无症状感染对 SARS-CoV-2 传播的贡献对于大流行控制至关重要。我们进行了一项回顾性流行病学研究，以描述意大利普利亚大区在 COVID-19 爆发的第一波疫情期间（2020 年 2 月 29 日至 7 月 7 日）发生的无症状 COVID-19 病例。我们分析了在一个区域平台上收集的数据，该平台旨在管理监测活动，即病例和接触者的调查和随访、接触者追踪以及实验室和临床数据收集。我们纳入了在适当随访期间实验室确诊的所有无症状病例，定义为感染 SARS-CoV-2 但未出现疾病症状/临床体征的人。在 2020 年 2 月 29 日至 7 月 7 日期间，在对 193757 次检测进行的总共 4536 例 COVID-19 诊断中，无症状 SARS-CoV-2 感染人群包括 903 例；无症状比例为 19.9%（95%CI：18.8-21.1%）；该比例随年龄增加而降低（OR：0.89，95%CI：0.83-0.96； = 0.001），在伴有基础合并症的个体中降低（OR：0.55，95%CI：0.41-0.73； < 0.001），在男性中降低（OR：0.69，95%CI：0.54-0.87； = 0.002）。无症状 SARS-CoV-2 RNA 阳性期的中位数为 19 天（IQR：14-31），在首次 PCR 检测阳性后 14 天，感染消除的累积比例为 74%。由于公共卫生界正在辩论无症状和晚期传播者是否可以在社区中持续传播病毒的问题，因此这些病例为深入了解 SARS-CoV-2 对人类宿主的适应提供了独特的机会。这对未来的 COVID-19 监测和预防具有重要意义。
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