West German Centre of Infectious Diseases, Department of Infectious Diseases, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany.
Institute for Virology, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany.
Viruses. 2022 Apr 1;14(4):746. doi: 10.3390/v14040746.
The novel, highly transmissible severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered a pandemic of acute respiratory illness worldwide and remains a huge threat to the healthcare system's capacity to respond to COVID-19. Elderly and immunocompromised patients are at increased risk for a severe course of COVID-19. These high-risk groups have been identified as developing diminished humoral and cellular immune responses. Notably, SARS-CoV-2 RNA remains detectable in nasopharyngeal swabs of these patients for a prolonged period of time. These factors complicate the clinical management of these vulnerable patient groups. To date, there are no well-defined guidelines for an appropriate duration of isolation for elderly and immunocompromised patients, especially in hospitals or nursing homes. The aim of the present study was to characterize at-risk patient cohorts capable of producing a replication-competent virus over an extended period after symptomatic COVID-19, and to investigate the humoral and cellular immune responses and infectivity to provide a better basis for future clinical management. In our cohort, the rate of positive viral cultures and the sensitivity of SARS-CoV-2 antigen tests correlated with higher viral loads. Elderly patients and patients with diabetes mellitus had adequate cellular and humoral immune responses to SARS-CoV-2 infection, while immunocompromised patients had reduced humoral and cellular immune responses. Our patient cohort was hospitalized for longer compared with previously published cohorts. Longer hospitalization was associated with a high number of nosocomial infections, representing a potential hazard for additional complications to patients. Most importantly, regardless of positive SARS-CoV-2 RNA detection, no virus was culturable beyond a cycle threshold (ct) value of 33 in the majority of samples. Our data clearly indicate that elderly and diabetic patients develop a robust immune response to SARS-CoV-2 and may be safely de-isolated at a ct value of more than 35.
新型、高传染性的严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）在全球范围内引发了急性呼吸道疾病大流行，仍然对医疗保健系统应对 COVID-19 的能力构成巨大威胁。老年和免疫功能低下的患者患 COVID-19 严重疾病的风险增加。这些高危人群被认为会产生减弱的体液和细胞免疫反应。值得注意的是，SARS-CoV-2 RNA 在这些患者的鼻咽拭子中可长时间检测到。这些因素使这些脆弱患者群体的临床管理复杂化。迄今为止，对于老年和免疫功能低下的患者，特别是在医院或疗养院，尚未制定适当的隔离时间的明确指南。本研究的目的是描述能够在 COVID-19 症状出现后长时间产生复制能力病毒的高危患者群体，并研究体液和细胞免疫反应和传染性，为未来的临床管理提供更好的基础。在我们的队列中，阳性病毒培养物的比率和 SARS-CoV-2 抗原检测的敏感性与较高的病毒载量相关。老年患者和糖尿病患者对 SARS-CoV-2 感染具有足够的细胞和体液免疫反应，而免疫功能低下的患者则具有减弱的体液和细胞免疫反应。与之前发表的队列相比，我们的患者队列住院时间更长。更长的住院时间与更多的医院感染相关，这对患者的其他并发症构成潜在危险。最重要的是，无论 SARS-CoV-2 RNA 是否呈阳性，在大多数样本中，超过循环阈值（ct）值 33 时，均无法培养出病毒。我们的数据清楚地表明，老年和糖尿病患者对 SARS-CoV-2 产生了强大的免疫反应，并且可以在 ct 值超过 35 时安全地解除隔离。
