Institute of Virology, Charité--Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany.
German Centre for Infection Research (DZIF), partner site Charité, 10117 Berlin, Germany.
Science. 2021 Jul 9;373(6551). doi: 10.1126/science.abi5273. Epub 2021 May 25.
Two elementary parameters for quantifying viral infection and shedding are viral load and whether samples yield a replicating virus isolate in cell culture. We examined 25,381 cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Germany, including 6110 from test centers attended by presymptomatic, asymptomatic, and mildly symptomatic (PAMS) subjects, 9519 who were hospitalized, and 1533 B.1.1.7 lineage infections. The viral load of the youngest subjects was lower than that of the older subjects by 0.5 (or fewer) log units, and they displayed an estimated ~78% of the peak cell culture replication probability; in part this was due to smaller swab sizes and unlikely to be clinically relevant. Viral loads above 10 copies per swab were found in 8% of subjects, one-third of whom were PAMS, with a mean age of 37.6 years. We estimate 4.3 days from onset of shedding to peak viral load (10 RNA copies per swab) and peak cell culture isolation probability (0.75). B.1.1.7 subjects had mean log viral load 1.05 higher than that of non-B.1.1.7 subjects, and the estimated cell culture replication probability of B.1.1.7 subjects was higher by a factor of 2.6.
量化病毒感染和脱落的两个基本参数是病毒载量和样本在细胞培养中是否产生复制病毒分离株。我们研究了德国 25381 例严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2)病例，其中包括 6110 例来自有症状前、无症状和轻度症状 (PAMS) 受试者就诊的检测中心、9519 例住院患者和 1533 例 B.1.1.7 谱系感染。年龄最小的患者的病毒载量比年龄较大的患者低 0.5（或更少）个对数单位，他们显示出估计的约 78%的峰值细胞培养复制概率；部分原因是拭子尺寸较小，不太可能具有临床相关性。在 8%的患者中发现每拭子 10 个拷贝以上的病毒载量，其中三分之一是 PAMS，平均年龄为 37.6 岁。我们估计从脱落到峰值病毒载量（每拭子 10 个 RNA 拷贝）和峰值细胞培养分离概率（0.75）的时间为 4.3 天。B.1.1.7 患者的平均病毒载量比非 B.1.1.7 患者高 1.05 个对数单位，B.1.1.7 患者的细胞培养复制概率估计高出 2.6 倍。
