Department of Medicine, Royal College of Surgeons in Ireland -Bahrain, Muharraq, Bahrain.
Department of Pathology, Bahrain Defense Force Hospital-Royal Medical Services, Riffa, Bahrain.
Front Immunol. 2022 Feb 14;13:812606. doi: 10.3389/fimmu.2022.812606. eCollection 2022.
B.1.1.7 (alpha) and B.1.617.2 (delta) variants of concern for SARS-CoV-2 have been reported to have differential infectivity and pathogenicity. Difference in recovery patterns across these variants and the interaction with vaccination status has not been reported in population-based studies.
The objective of this research was to study the length of stay and temporal trends in RT-PCR cycle times (Ct) across alpha and delta variants of SARS-CoV-2 between vaccinated and unvaccinated individuals.
Participants consisted of patients admitted to national COVID-19 treatment facilities if they had a positive RT-PCR test for SARS-CoV-2, and analysis of variants was performed (using whole genome sequencing). Information on vaccination status, age, sex, cycle times (Ct) for four consecutive RT-PCR tests conducted during hospital stay, and total length of hospital stay for each participant were ascertained from electronic medical records.
Patients infected with the delta variant were younger (mean age = 35years vs 39 years for alpha, p<0.001) and had lesser vaccination coverage (54% vs 72% for alpha, p<0.001). RT-PCR Ct values were similar for both variants at the baseline test; however by the fourth test, delta variant patients had significantly lower Ct values (27 vs 29, p=0.05). Length of hospital stay was higher in delta variant patients in vaccinated (3 days vs 2.9 days for alpha variant) as well as in unvaccinated patients (5.2 days vs 4.4 days for alpha variant, p<0.001). Hazards of hospital discharge after adjusting for vaccination status, age, and sex was higher for alpha variant infections (HR=1.2, 95% CI: 1.01-1.41, p=0.029).
Patients infected with the delta variant of SARS-CoV-2 were found to have a slower recovery as indicated by longer length of stay and higher shedding of the virus compared to alpha variant infections, and this trend was consistent in both vaccinated and unvaccinated patients.
已报告 B.1.1.7（阿尔法）和 B.1.617.2（德尔塔）变异株对 SARS-CoV-2 的传染性和致病性存在差异。尚未在基于人群的研究中报告这些变异株的恢复模式差异以及与疫苗接种状态的相互作用。
本研究旨在研究接种和未接种个体中 SARS-CoV-2 的阿尔法和德尔塔变异株的住院时间和实时聚合酶链反应（RT-PCR）循环时间（Ct）的时间趋势。
如果患者的 SARS-CoV-2 RT-PCR 检测呈阳性，参与者将被纳入国家 COVID-19 治疗设施住院治疗，对变异株进行分析（使用全基因组测序）。从电子病历中确定每个参与者的疫苗接种状态、年龄、性别、住院期间连续进行的四次 RT-PCR 测试的循环时间（Ct）以及总住院时间。
感染德尔塔变异株的患者更年轻（平均年龄=35 岁 vs 阿尔法变异株的 39 岁，p<0.001），疫苗接种率较低（54% vs 阿尔法变异株的 72%，p<0.001）。两种变异株的基线测试 RT-PCR Ct 值相似；然而，第四次测试时，德尔塔变异株患者的 Ct 值明显更低（27 对 29，p=0.05）。在接种疫苗和未接种疫苗的患者中，德尔塔变异株患者的住院时间均较长（接种疫苗的患者为 3 天，阿尔法变异株为 2.9 天；未接种疫苗的患者为 5.2 天，阿尔法变异株为 4.4 天，p<0.001）。调整疫苗接种状态、年龄和性别后，阿尔法变异株感染后出院的风险更高（HR=1.2，95%CI：1.01-1.41，p=0.029）。
与阿尔法变异株感染相比，感染 SARS-CoV-2 的德尔塔变异株的患者发现恢复较慢，表现为住院时间更长，病毒脱落量更高，这一趋势在接种疫苗和未接种疫苗的患者中均一致。
