Gomez Marti Juan Luis, Mays Ashley, McCullough Melissa, Wells Alan, Phan Tung
Department of Pathology, University of Pittsburgh, PA, USA.
Clinical Microbiology Laboratory, UPMC Hospital System, Pittsburgh, PA, USA.
Microbiol Insights. 2022 Mar 23;15:11786361221087537. doi: 10.1177/11786361221087537. eCollection 2022.
The Delta SARS-CoV-2 variant is very infectious, and it is spreading quickly during this pandemic. In the study, we compared viral loads estimated by means of the Ct values emerging from RT-PCR swab tests in surging cases infected with the SARS-CoV-2 Delta variant in the fourth wave of COVID-19 with the three prior waves. The data comprised viral loads from positive cases detected within the UPMC health care system in Allegheny County, Pennsylvania. A total of 2059 upper airway samples were collected and tested for SARS-CoV-2 positive by RT-PCR during March 2020 to September 2021. We did not observe significant difference in viral load difference between the third (December 2020 to January 2021) and fourth (June 2021 to September 2021) waves; however, they had the higher viral load than the first (March 2020 to June 2020) and second waves (June 2020 to August 2020). We did find an age-related effect with the elderly presenting with lower viral loads, which was also seen in the earlier waves. However, the level of the viral loads in the fourth wave in the respect of the previous ones was not sufficiently increased to change our testing strategies by means of increased use of rapid antigen tests (RAT).
新冠病毒德尔塔变种传染性极强，在此次疫情大流行期间传播迅速。在这项研究中，我们将新冠病毒德尔塔变种感染激增病例的逆转录聚合酶链反应（RT-PCR）拭子检测得出的Ct值所估算的病毒载量，与新冠疫情前三波以及第四波疫情进行了比较。数据包括宾夕法尼亚州阿勒格尼县匹兹堡大学医学中心（UPMC）医疗系统内检测出的阳性病例的病毒载量。2020年3月至2021年9月期间，共采集了2059份上呼吸道样本，并通过RT-PCR检测出新冠病毒呈阳性。我们未观察到第三波（2020年12月至2021年1月）和第四波（2021年6月至2021年9月）疫情之间病毒载量存在显著差异；然而，它们的病毒载量高于第一波（2020年3月至2020年6月）和第二波（2020年6月至2020年8月）。我们确实发现了一种与年龄相关的效应，即老年人的病毒载量较低，这在早期疫情波次中也有体现。然而，第四波疫情的病毒载量水平相较于之前几波，并未显著增加到需要通过增加使用快速抗原检测（RAT）来改变我们的检测策略的程度。
