Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545.
New Mexico Consortium, Los Alamos, NM 87544.
Proc Natl Acad Sci U S A. 2021 Dec 7;118(49). doi: 10.1073/pnas.2111477118.
The within-host viral kinetics of SARS-CoV-2 infection and how they relate to a person's infectiousness are not well understood. This limits our ability to quantify the impact of interventions on viral transmission. Here, we develop viral dynamic models of SARS-CoV-2 infection and fit them to data to estimate key within-host parameters such as the infected cell half-life and the within-host reproductive number. We then develop a model linking viral load (VL) to infectiousness and show a person's infectiousness increases sublinearly with VL and that the logarithm of the VL in the upper respiratory tract is a better surrogate of infectiousness than the VL itself. Using data on VL and the predicted infectiousness, we further incorporated data on antigen and RT-PCR tests and compared their usefulness in detecting infection and preventing transmission. We found that RT-PCR tests perform better than antigen tests assuming equal testing frequency; however, more frequent antigen testing may perform equally well with RT-PCR tests at a lower cost but with many more false-negative tests. Overall, our models provide a quantitative framework for inferring the impact of therapeutics and vaccines that lower VL on the infectiousness of individuals and for evaluating rapid testing strategies.
宿主内的 SARS-CoV-2 感染病毒动力学及其与个体传染性的关系尚不清楚。这限制了我们定量评估干预措施对病毒传播影响的能力。在此，我们开发了 SARS-CoV-2 感染的病毒动力学模型，并对其进行拟合，以估计关键的宿主内参数，如感染细胞半衰期和宿主内繁殖数。然后，我们开发了一个将病毒载量 (VL) 与传染性联系起来的模型，并表明一个人的传染性随 VL 呈亚线性增加，而上呼吸道的 VL 对数比 VL 本身更能反映传染性。利用 VL 和预测的传染性数据，我们进一步纳入了抗原和 RT-PCR 检测数据，并比较了它们在检测感染和预防传播方面的有用性。我们发现，在假设检测频率相等的情况下，RT-PCR 检测比抗原检测更有效；然而，在成本更低的情况下，更频繁的抗原检测可能与 RT-PCR 检测同样有效，但假阴性检测会更多。总体而言，我们的模型为推断降低 VL 的疗法和疫苗对个体传染性的影响提供了一个定量框架，并为评估快速检测策略提供了参考。
