We aimed to generate an unbiased estimate of the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in 4 urban counties in Utah, USA. We used a multistage sampling design to randomly select community-representative participants >12 years of age. During May 4–June 30, 2020, we collected serum samples and survey responses from 8,108 persons belonging to 5,125 households. We used a qualitative chemiluminescent microparticle immunoassay to detect SARS-CoV-2 IgG in serum samples. We estimated the overall seroprevalence to be 0.8%. The estimated seroprevalence-to-case count ratio was 2.5, corresponding to a detection fraction of 40%. Only 0.2% of participants from whom we collected nasopharyngeal swab samples had SARS-CoV-2–positive reverse transcription PCR results. SARS-CoV-2 antibody prevalence during the study was low, and prevalence of PCR-positive cases was even lower. The comparatively high SARS-CoV-2 detection rate (40%) demonstrates the effectiveness of Utah’s testing strategy and public health response.

我们旨在对美国犹他州 4 个城市县的严重急性呼吸系统综合症冠状病毒 2 (SARS-CoV-2) 感染发生率进行无偏估计。我们使用多阶段抽样设计来随机选择社区代表参与者>12岁。在 2020 年 5 月 4 日至 6 月 30 日期间，我们收集了属于 5,125 个家庭的 8,108 人的血清样本和调查答复。我们使用定性化学发光微粒免疫测定法检测血清样本中的 SARS-CoV-2 IgG。我们估计总体血清阳性率为 0.8%。估计的血清阳性率与病例计数比为 2.5，对应于 40% 的检出率。在我们收集鼻咽拭子样本的参与者中，只有 0.2% 的逆转录 PCR 结果为 SARS-CoV-2 阳性。研究期间 SARS-CoV-2 抗体流行率较低，PCR 阳性病例的流行率更低。相对较高的 SARS-CoV-2 检出率 (40%) 证明了犹他州检测策略和公共卫生应对措施的有效性。