Yinda Claude Kwe, Port Julia R, Bushmaker Trenton, Schulz Jonathan E, Gallogly Shane, Fischer Robert J, Munster Vincent J
Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.
Npj Viruses. 2024 Jan 9;2(1):2. doi: 10.1038/s44298-023-00011-3.
Several human respiratory viruses display a clear seasonal pattern with a higher incidence in the winter season in temperate regions. We previously determined that SARS-CoV-2 is more stable at low-temperature and low-humidity conditions compared to warmer temperature and higher-humidity. To determine if this translates into differential airborne transmission rates in vivo, we performed airborne transmission experiments in the Syrian hamster model under three different environmental conditions (10 °C, 45% relative humidity (RH), 22 °C, 45% RH, and 27 °C, 65% RH). We compared the ancestral SARS-CoV-2 Lineage A with the more transmissible Delta Variant of Concern (VOC). Airborne transmission was evaluated using SARS-CoV-2 infected donor animals at 24 h post inoculation. Sentinels were placed at a 90 cm distance in a transmission set-up and exposed for 1-h to infected donor animals. While environmental conditions moderately impacted lung RNA titers, the shedding kinetics of the donors were not affected by the environmental conditions and did not differ significantly between variants on day 1. Overall, the highest transmission efficiency was observed at 22 °C, 40%RH for Delta (62.5%, based on seroconversion), and ranged between 37.5 and 50% for all other conditions. However, these differences were not significant. To elucidate this further, we performed aerosol stability comparisons and found that infectious virus remained stable during a 1-h time window across all conditions. Our data suggest that even when environmental conditions affect the stability of SARS-CoV-2, this may not directly be translatable to measurable impacts on transmission in an experimental setting when exposure time is restricted.
几种人类呼吸道病毒呈现出明显的季节性模式，在温带地区冬季发病率较高。我们之前确定，与较高温度和湿度相比，严重急性呼吸综合征冠状病毒2（SARS-CoV-2）在低温低湿条件下更稳定。为了确定这是否会转化为体内不同的空气传播率，我们在叙利亚仓鼠模型中于三种不同环境条件（10°C、45%相对湿度（RH）、22°C、45%RH和27°C、65%RH）下进行了空气传播实验。我们将原始的SARS-CoV-2 A谱系与传播性更强的关注变异株德尔塔（Delta）进行了比较。在接种后24小时，使用感染了SARS-CoV-2的供体动物评估空气传播情况。在传播装置中，将哨兵动物放置在90厘米的距离处，使其暴露于感染的供体动物1小时。虽然环境条件对肺部RNA滴度有一定影响，但供体的病毒脱落动力学不受环境条件影响，且在第1天不同变异株之间无显著差异。总体而言，德尔塔毒株在22°C、40%RH时观察到最高传播效率（基于血清转化为62.5%），在所有其他条件下传播效率在37.5%至50%之间。然而，这些差异并不显著。为了进一步阐明这一点，我们进行了气溶胶稳定性比较，发现所有条件下感染性病毒在1小时时间窗口内均保持稳定。我们的数据表明，即使环境条件影响SARS-CoV-2的稳定性，但当暴露时间受到限制时，这在实验环境中可能不会直接转化为对传播的可测量影响。
