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) log₁₀ 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 10⁹ 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 (10^8.1 RNA copies per swab) and peak cell culture isolation probability (0.75). B.1.1.7 subjects had mean log₁₀ 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以及样品是否在细胞培养物中产生复制的病毒分离株。我们检查了德国 25,381 例严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 病例，其中 6110 例来自测试中心，有症状前、无症状和轻度症状 (PAMS) 受试者，9519 例住院患者，1533 例 B.1.1 .7 谱系感染。最年轻受试者的病毒载量比年长受试者低 0.5（或更少）log ₁₀单位，并且他们显示出约 78% 的峰值细胞培养复制概率；部分原因是拭子尺寸较小，不太可能与临床相关。 8% 的受试者中发现每个拭子的病毒载量超过 10 ^{9 个}拷贝，其中三分之一是 PAMS，平均年龄为 37.6 岁。我们估计从开始脱落到病毒载量峰值（每个拭子 10 ^8.1 RNA 拷贝）和细胞培养分离概率峰值 (0.75) 需要 4.3 天。 B.1.1.7受试者的平均log ₁₀病毒载量比非B.1.1.7受试者高1.05，并且B.1.1.7受试者的估计细胞培养物复制概率高出2.6倍。