Department of Pathology, School of Medicine, Stanford, CA, United States.
Department of Medicine (Biomedical Informatics), School of Medicine, Stanford, CA, United States.
J Clin Virol. 2020 Aug;129:104477. doi: 10.1016/j.jcv.2020.104477. Epub 2020 May 30.
Current guidelines for returning health care workers (HCW) to service after a positive SARS-CoV-2 RT-PCR test and ceasing of transmission precautions for patients is based on two general strategies. A test-based strategy that requires negative respiratory RT-PCR tests obtained after the resolution of symptoms. Alternatively, due to the limited availability of testing, many sites employ a symptom-based strategy that recommends excluding HCW from the workforce and keeping patients on contact precautions until a fixed period of time has elapsed from symptom recovery. The underlying assumption of the symptom-based strategy is that waiting for a fixed period of time is a surrogate for negative RT-PCR testing, which itself is a surrogate for the absence of shedding infectious virus.
To better understand the appropriate length of symptom based return to work and contact precaution strategies.
We performed an observational analysis of 150 patients and HCW that transitioned from RT-PCR SARS-CoV-2 positive to negative over the course of 2 months at a US academic medical center.
We found that the average time to transition from RT-PCR positive to negative was 24 days after symptom onset and 10 % remained positive even 33 days after symptom onset. No difference was seen in HCW and patients.
These findings suggest until definitive evidence of the length of infective viral shedding is obtained that the fixed length of time before returning to work or ceasing contract precautions be revised to over one-month.
目前，针对新冠病毒 RT-PCR 检测呈阳性的医护人员（HCW）重返工作岗位以及停止对患者采取传播预防措施的指南，主要基于两种策略。一种是基于检测的策略，要求在症状缓解后获得阴性呼吸道 RT-PCR 检测结果。另一种策略，由于检测资源有限，许多机构采用基于症状的策略，建议将 HCW 从工作场所中排除，并对患者采取接触预防措施，直到从症状恢复开始计算的固定时间段过去。基于症状的策略的基本假设是，等待固定时间段是阴性 RT-PCR 检测的替代方法，而阴性 RT-PCR 检测本身则是传染性病毒脱落不存在的替代方法。
为了更好地了解基于症状的重返工作和接触预防策略的适当时间长度。
我们对美国一所学术医疗中心的 150 名患者和 HCW 进行了观察性分析，这些患者和 HCW 的 RT-PCR 检测结果从新冠病毒阳性转为阴性，历时 2 个月。
我们发现，从 RT-PCR 阳性转为阴性的平均时间是症状出现后 24 天，即使在症状出现后 33 天，仍有 10%的患者 RT-PCR 结果为阳性。HCW 和患者之间没有差异。
这些发现表明，在获得关于传染性病毒脱落的确切时间长度的证据之前，应将重返工作岗位或停止接触预防措施的固定时间段修改为一个月以上。
