In the early phases of the SARS coronavirus type 2 (SARS-CoV-2) pandemic, testing focused on individuals fitting a strict case definition involving a limited set of symptoms together with an identified epidemiological risk, such as contact with an infected individual or travel to a high-risk area. To assess whether this impaired our ability to detect and control early introductions of the virus into the UK, we PCR-tested archival specimens collected on admission to a large UK teaching hospital who retrospectively were identified as having a clinical presentation compatible with COVID-19. In addition, we screened available archival specimens submitted for respiratory virus diagnosis, and dating back to early January 2020, for the presence of SARS-CoV-2 RNA. Our data provides evidence for widespread community circulation of SARS-CoV-2 in early February 2020 and into March that was undetected at the time due to restrictive case definitions informing testing policy. Genome sequence data showed that many of these early cases were infected with a distinct lineage of the virus. Sequences obtained from the first officially recorded case in Nottinghamshire - a traveller returning from Daegu, South Korea – also clustered with these early UK sequences suggesting acquisition of the virus occurred in the UK and not Daegu. Analysis of a larger sample of sequences obtained in the Nottinghamshire area revealed multiple viral introductions, mainly in late February and through March. These data highlight the importance of timely and extensive community testing to prevent future widespread transmission of the virus.

中文翻译：

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对英国常规呼吸道样本的回顾性筛查揭示了未检测到的社区传播，并错失了针对 SARS-CoV-2 的干预机会

在 SARS 冠状病毒 2 型 (SARS-CoV-2) 大流行的早期阶段，检测的重点是符合严格病例定义的个体，涉及一组有限的症状以及已确定的流行病学风险，例如与感染者接触或旅行到高风险地区。为了评估这是否损害了我们检测和控制病毒早期传入英国的能力，我们对英国一家大型教学医院入院时收集的档案标本进行了 PCR 检测，这些标本被回顾性地鉴定为具有与 COVID-19 相符的临床表现。此外，我们还对提交用于呼吸道病毒诊断的可用档案样本（可追溯至 2020 年 1 月上旬）进行了筛查，以确定是否存在 SARS-CoV-2 RNA。我们的数据提供了 SARS-CoV-2 在 2020 年 2 月上旬和 3 月份广泛社区传播的证据，当时由于检测政策中的病例定义限制而未被发现。基因组序列数据显示，许多早期病例都感染了一种独特的病毒谱系。从诺丁汉郡第一个正式记录的病例（一名从韩国大邱返回的旅行者）获得的序列也与这些早期的英国序列聚集在一起，表明该病毒的感染发生在英国而不是大邱。对诺丁汉郡地区获得的更大序列样本的分析显示，病毒多次传入，主要是在二月下旬和三月期间。这些数据凸显了及时和广泛的社区检测对于防止病毒未来广泛传播的重要性。