C.U.R.E. (University Center for Liver Disease Research and Treatment), Liver Unit, Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy.
Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy; IRCCS Don Carlo Gnocchi Foundation, Florence, Italy.
Int J Infect Dis. 2021 Mar;104:696-700. doi: 10.1016/j.ijid.2021.01.068. Epub 2021 Feb 2.
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has heavily impacted Italy. The government's restriction measures have attenuated the burden on hospitals. The association of high viral replication with disease severity suggests the potential for lower viral load in milder clinical presentations.
The reverse-transcription-polymerase-chain-reaction (RT-PCR) profile of 944 consecutive, non-replicate, positive retropharyngeal swabs was collected from 3 March to 8 June 2020 to investigate the temporal profile of SARS-CoV-2 viral load in the region of Capitanata, Apulia. Cycle threshold (Ct) values of 3 targets (N [nucleocapsid protein], E [envelope protein] and RdRP [RNA-dependent RNA-polymerase]) were analysed.
The median Ct values of the 3 targets increased considerably over the study period, showing a progressive and constant weekly change. The negative detection rate of E and RdRP increased over time. These data suggest that SARS-CoV-2 viral load progressively decreased along the outbreak course. During the first epidemic peak (March and April) the viral load among patients >80-years was significantly higher than for younger subjects. However, in May this age-dependent difference disappeared, underlying viral load reduction in the elderly.
An attenuation of viral transmission or pathogenicity during the epidemic course is suggested, likely due to restriction measures, although viral factors might also be considered.
严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）大流行严重影响了意大利。政府的限制措施减轻了医院的负担。高病毒复制与疾病严重程度相关表明，在较轻的临床表现中，病毒载量可能较低。
2020 年 3 月 3 日至 6 月 8 日，连续收集了 944 例非重复阳性咽后拭子的逆转录-聚合酶链反应（RT-PCR）谱，以研究普利亚大区卡皮塔诺纳地区 SARS-CoV-2 病毒载量的时间分布。分析了 3 个靶标（N[核衣壳蛋白]、E[包膜蛋白]和 RdRP[RNA 依赖性 RNA 聚合酶]）的循环阈值（Ct）值。
研究期间，3 个靶标的中位 Ct 值显著升高，呈渐进性和持续的每周变化。E 和 RdRP 的阴性检出率随时间增加。这些数据表明，SARS-CoV-2 病毒载量在疫情发展过程中逐渐下降。在第一波疫情高峰（3 月和 4 月），>80 岁患者的病毒载量明显高于年轻患者。然而，5 月时这种年龄相关的差异消失了，表明老年人的病毒载量减少。
提示在疫情发展过程中病毒传播或毒力减弱，可能是由于限制措施，但也可能考虑到病毒因素。
