Coronavirus disease 2019 (COVID-19) was first diagnosed in Scotland on 1 March 2020. During the first month of the outbreak, 2,641 cases of COVID-19 led to 1,832 hospital admissions, 207 intensive care admissions and 126 deaths. We aimed to identify the source and number of introductions of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into Scotland using a combined phylogenetic and epidemiological approach. Sequencing of 1,314 SARS-CoV-2 viral genomes from available patient samples enabled us to estimate that SARS-CoV-2 was introduced to Scotland on at least 283 occasions during February and March 2020. Epidemiological analysis confirmed that early introductions of SARS-CoV-2 originated from mainland Europe (the majority from Italy and Spain). We identified subsequent early outbreaks in the community, within healthcare facilities and at an international conference. Community transmission occurred after 2 March, 3 weeks before control measures were introduced. Earlier travel restrictions or quarantine measures, both locally and internationally, would have reduced the number of COVID-19 cases in Scotland. The risk of multiple reintroduction events in future waves of infection remains high in the absence of population immunity.

2019 年冠状病毒病 (COVID-19) 于 2020 年 3 月 1 日在苏格兰首次确诊。在疫情爆发的第一个月，共有 2,641 例 COVID-19 病例，导致 1,832 人入院、207 人入院重症监护和 126 人死亡。我们的目的是采用系统发育和流行病学相结合的方法来确定严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 传入苏格兰的来源和数量。对现有患者样本中的 1,314 个 SARS-CoV-2 病毒基因组进行测序，使我们能够估计 2020 年 2 月至 3 月期间，至少有 283 次 SARS-CoV-2 被引入苏格兰。流行病学分析证实，SARS-CoV-2 的早期引入2起源于欧洲大陆（大部分来自意大利和西班牙）。我们随后在社区、医疗机构内和国际会议上发现了早期疫情爆发。社区传播发生在3月2日之后，即采取控制措施前3周。早期的本地和国际旅行限制或检疫措施本可以减少苏格兰的 COVID-19 病例数量。在缺乏人群免疫力的情况下，未来感染浪潮中多次重新引入事件的风险仍然很高。