BACKGROUND Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can spread rapidly within skilled nursing facilities. After identification of a case of Covid-19 in a skilled nursing facility, we assessed transmission and evaluated the adequacy of symptom-based screening to identify infections in residents. METHODS We conducted two serial point-prevalence surveys, 1 week apart, in which assenting residents of the facility underwent nasopharyngeal and oropharyngeal testing for SARS-CoV-2, including real-time reverse-transcriptase polymerase chain reaction (rRT-PCR), viral culture, and sequencing. Symptoms that had been present during the preceding 14 days were recorded. Asymptomatic residents who tested positive were reassessed 7 days later. Residents with SARS-CoV-2 infection were categorized as symptomatic with typical symptoms (fever, cough, or shortness of breath), symptomatic with only atypical symptoms, presymptomatic, or asymptomatic. RESULTS Twenty-three days after the first positive test result in a resident at this skilled nursing facility, 57 of 89 residents (64%) tested positive for SARS-CoV-2. Among 76 residents who participated in point-prevalence surveys, 48 (63%) tested positive. Of these 48 residents, 27 (56%) were asymptomatic at the time of testing; 24 subsequently developed symptoms (median time to onset, 4 days). Samples from these 24 presymptomatic residents had a median rRT-PCR cycle threshold value of 23.1, and viable virus was recovered from 17 residents. As of April 3, of the 57 residents with SARS-CoV-2 infection, 11 had been hospitalized (3 in the intensive care unit) and 15 had died (mortality, 26%). Of the 34 residents whose specimens were sequenced, 27 (79%) had sequences that fit into two clusters with a difference of one nucleotide. CONCLUSIONS Rapid and widespread transmission of SARS-CoV-2 was demonstrated in this skilled nursing facility. More than half of residents with positive test results were asymptomatic at the time of testing and most likely contributed to transmission. Infection-control strategies focused solely on symptomatic residents were not sufficient to prevent transmission after SARS-CoV-2 introduction into this facility.

中文翻译：

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熟练护理设施中的症状前SARS-CoV-2感染和传播。

背景技术严重的急性呼吸系统综合症冠状病毒2（SARS-CoV-2）感染可在熟练的护理设施内迅速传播。在熟练的护理机构中发现一例Covid-19病例后，我们评估了传播情况并评估了基于症状的筛查是否足以识别居民中的感染。方法我们进行了两次连续性点流行病调查，相隔1周，其中对设施的居民进行了SARS-CoV-2的鼻咽和口咽测试，包括实时逆转录聚合酶链反应（rRT-PCR），病毒文化和测序。记录在过去14天内出现的症状。7天后对评估为阳性的无症状居民进行了重新评估。患有SARS-CoV-2感染的居民可分为典型症状（发烧，咳嗽或呼吸急促）的症状，仅具有非典型症状的症状，有症状的或无症状的。结果在该熟练护理机构中，一名居民的首次阳性测试结果后二十三天，在89名居民中，有57名（64％）的SARS-CoV-2呈阳性。在参加点流行度调查的76位居民中，有48位（63％）测试为阳性。在这48位居民中，有27位（56％）在测试时无症状。随后出现24种症状（中位发病时间为4天）。来自这24名有症状前居民的样本的rRT-PCR循环阈值中位数为23.1，从17名居民中回收了活病毒。截至4月3日，在57名SARS-CoV-2感染居民中，11人已住院（重症监护病房3人），15人死亡（死亡率，26％）。在对34个样本进行了测序的居民中，有27个（79％）的序列适合两个簇，但相差一个核苷酸。结论在该熟练护理机构中证明了SARS-CoV-2的快速和广泛传播。测试结果呈阳性的居民中有一半以上在测试时无症状，最有可能导致传播。仅针对有症状居民的感染控制策略不足以防止SARS-CoV-2进入该设施后传播。结论在该熟练护理机构中证明了SARS-CoV-2的快速和广泛传播。测试结果呈阳性的居民中，有一半以上在测试时无症状，最有可能导致传播。仅针对有症状居民的感染控制策略不足以防止SARS-CoV-2进入该设施后传播。结论在该熟练护理机构中证明了SARS-CoV-2的快速和广泛传播。测试结果呈阳性的居民中，有一半以上在测试时无症状，最有可能导致传播。仅针对有症状居民的感染控制策略不足以防止SARS-CoV-2进入该设施后传播。