Department of Laboratory Medicine and Pathology, University of Washington School of Medicinegrid.471394.c, Seattle, Washington, USA.
Department of Biomedical Informatics and Medical Education, University of Washington School of Medicinegrid.471394.c, Seattle, Washington, USA.
J Clin Microbiol. 2022 Dec 21;60(12):e0137122. doi: 10.1128/jcm.01371-22. Epub 2022 Nov 21.
Recently, a sustained human-to-human outbreak of monkeypox virus (MPXV), a member of the genus, which includes the etiologic agent of smallpox, has been documented in multiple nonendemic countries, including the United States. Prior to June 2022, testing in the United States was limited to public health labs and the Centers for Disease Control and Prevention. Following recognition of the scope of the outbreak, testing for MPXV has expanded into clinical laboratories. Here, we examine epidemiological characteristics, specimen collection practices, and cycle threshold (Ct) values for 10,019 MPXV PCR tests performed at two reference laboratories. Results from both laboratories support public health data showing a high positivity rate in men (>30%) and those ages 30 to 49 (25 to 35%). The overall positivity rate decreased during the study period but remains elevated (~20%). There was a significant difference in Ct values between laboratories (ARUP 23.9 versus UW 25.4) and collection method (22.8 for dry swab versus 24.4 for VTM), likely reflecting slight differences in specimen processing. When multiple specimens were collected for a single individual, the overall result concordance rate was greater than 95%, with less than 1.5% of individuals receiving three or more tests having a single positive result. Compared to the overall positive cohort, individuals with three or more swabs collected and a single positive result had significantly higher Ct values (22.9 versus 35.0). Intriguingly, individuals aged 50 to 59 years old had a significantly different viral load distribution than those found in younger age groups, potentially associated with prior vaccinia virus vaccination. These results provide an early snapshot of testing in the United States during the monkeypox virus outbreak and support restricting the number of swabs collected per individual.
最近，在多个非流行国家，包括美国，已经记录到了猴痘病毒（MPXV）的持续人际间爆发。在 2022 年 6 月之前，美国的检测仅限于公共卫生实验室和疾病控制与预防中心。在认识到疫情的范围后，对 MPXV 的检测已经扩展到临床实验室。在这里，我们检查了在两个参考实验室进行的 10019 次 MPXV PCR 检测的流行病学特征、标本采集实践和循环阈值（Ct）值。来自两个实验室的结果都支持公共卫生数据，表明男性（>30%）和 30 至 49 岁（25 至 35 岁）人群的阳性率很高。在研究期间，总体阳性率有所下降，但仍处于高位（~20%）。两个实验室之间的 Ct 值存在显著差异（ARUP 为 23.9，UW 为 25.4）和采集方法（干拭子为 22.8，VTM 为 24.4），这可能反映了标本处理上的细微差异。当对单个个体采集多个标本时，总体结果的一致性率大于 95%，不到 1.5%的个体接受三次或更多次检测，只有一次阳性结果。与总体阳性队列相比，采集三次或更多拭子且只有一次阳性结果的个体的 Ct 值显著更高（22.9 与 35.0）。有趣的是，50 至 59 岁的个体与年轻年龄组相比，病毒载量分布有显著差异，这可能与先前接种牛痘病毒有关。这些结果提供了在美国猴痘病毒爆发期间检测的早期情况，并支持限制每个个体采集的拭子数量。
