Central Research Institute of Epidemiology of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing, 111123, Moscow, Russia.
BMC Infect Dis. 2021 Sep 16;21(1):959. doi: 10.1186/s12879-021-06664-w.
The dual infection with SARS-CoV-2 is poorly described and is currently under discussion. We present a study of two strains of SARS-CoV-2 detected in the same patient during the same disease presentation.
A patient in their 90 s was hospitalised with fever. Oropharyngeal swab obtained on the next day (sample 1) tested positive for SARS-CoV-2. Five days later, the patient was transferred to the ICU (intensive care unit) of the hospital specialising in the treatment of COVID-19 patients, where the patient's condition progressively worsened and continuous oxygen insufflation was required. Repeated oropharyngeal swab (sample 2), which was taken eight days after the first one, also tested positive for SARS-CoV-2. After 5 days of ICU treatment, the patient died. The cause of death was a coronavirus infection, which progressed unfavourably due to premorbid status. We have performed sequencing of full SARS-CoV-2 genomes from oropharyngeal swabs obtained eight days apart. Genomic analysis revealed the presence of two genetically distant SARS-CoV-2 strains in both swabs. Detected strains belong to different phylogenetic clades (GH and GR) and differ in seven nucleotide positions. The relative abundance of strains was 70% (GH) and 30% (GR) in the first swab, and 3% (GH) and 97% (GR) in the second swab.
Our findings suggest that the patient was infected by two genetically distinct SARS-CoV-2 strains at the same time. One of the possible explanations is that the second infection was hospital-acquired. Change of the dominant strain ratio during disease manifestation could be explained by the advantage or higher virulence of the GR clade strain.
SARS-CoV-2 的双重感染描述甚少，目前仍存在争议。我们报告了一例在同一患者的同一疾病发作期间同时检测到两种 SARS-CoV-2 毒株的病例。
一位 90 多岁的患者因发热住院。次日获得的咽拭子标本（样本 1）检测出 SARS-CoV-2 阳性。5 天后，患者转至专门治疗 COVID-19 患者的医院 ICU，患者病情逐渐恶化，需要持续吸氧。第一次咽拭子 8 天后再次进行咽拭子检测（样本 2），结果仍为 SARS-CoV-2 阳性。在 ICU 治疗 5 天后，患者死亡。死亡原因是冠状病毒感染，由于合并疾病状态，病情恶化。我们对相隔 8 天获得的咽拭子进行了全 SARS-CoV-2 基因组测序。基因组分析显示，两个咽拭子中均存在两种遗传上不同的 SARS-CoV-2 株。检测到的株属于不同的系统发育枝（GH 和 GR），在 7 个核苷酸位置存在差异。第一份咽拭子中两种株的相对丰度分别为 70%（GH）和 30%（GR），第二份咽拭子中分别为 3%（GH）和 97%（GR）。
我们的研究结果表明，患者同时感染了两种遗传上不同的 SARS-CoV-2 株。一种可能的解释是第二次感染是医院获得性的。在疾病表现过程中优势株比例的变化可能是由于 GR 枝株的优势或更高的毒力所致。
