背景:引起关注的SARS-CoV-2变体(VOCs)出现并迅速取代了世界范围内的原始毒株。这些新变体的传播性增加导致感染增加,住院治疗,和死亡率。然而,在存在关键公共卫生措施和各种社会健康决定因素(SDOHs)的情况下,缺乏回顾性调查来检查所有主要VOCs的严重程度.
目的:本研究旨在在异质性SDOH和疫苗接种推广的背景下,对COVID-19VOCs的临床严重程度进行回顾性评估。
方法:我们使用基于人群的回顾性队列设计,数据来自不列颠哥伦比亚省COVID-19队列,一个链接的省级监控平台。评估相对严重程度(住院,重症监护病房[ICU]入院,和死亡)的伽马,Delta,和2021年相对于阿尔法的Omicron感染,我们使用逆概率处理加权Cox比例风险模型。我们还对未接种疫苗的个体进行了亚分析,评估的严重程度在VOCs和SDOH之间存在差异。
结果:我们包括91,964名感染SARS-CoV-2VOC的个体(Alpha:n=20,487,22.28%;Gamma:n=15,223,16.55%;Delta:n=49,161,53.46%;和Omicron:n=7093,7.71%)。就住院而言,三角洲与最严重的疾病相关,ICU入院,和死亡(住院:调整后的风险比[aHR]2.00,95%CI1.92-2.08;ICU:aHR2.05,95%CI1.91-2.20;死亡:aHR3.70,95%CI3.23-4.25相对于Alpha),其次是伽玛,然后是Omicron和Alpha。在未接种疫苗的个体亚分析中,VOC的相对严重程度保持相似,尽管未接种疫苗的人住院的Delta和Omicron感染人数比例是完全接种疫苗的人的2倍。关于SDOHs,在所有挥发性有机化合物中,收入较低的地区住院人数比例较高,而在α和γ感染中,2种共同传播的挥发性有机化合物,在种族化的群体中发现了住院的差异分布。
结论:我们的研究为不列颠哥伦比亚省COVID-19大流行期间的所有VOCs提供了可靠的严重程度估计,加拿大。相对于阿尔法,我们发现三角洲是最严重的,其次是Gamma和Omicron.这项研究强调了靶向测试和测序的重要性,以确保及时检测和准确估计新兴变异的严重程度。它进一步阐明了疫苗接种覆盖率和SDOH在大流行防备背景下的重要性,以支持优先分配给资源有限或少数群体。
BACKGROUND: SARS-CoV-2 variants of concern (VOCs) emerged and rapidly replaced the original strain worldwide. The increased transmissibility of these new variants led to increases in infections, hospitalizations, and mortality. However, there is a scarcity of retrospective investigations examining the severity of all the main VOCs in presence of key public health measures and within various social determinants of health (SDOHs).
OBJECTIVE: This study aims to provide a retrospective assessment of the clinical severity of COVID-19 VOCs in the context of heterogenous SDOHs and vaccination rollout.
METHODS: We used a population-based retrospective cohort design with data from the British Columbia COVID-19 Cohort, a linked provincial surveillance platform. To assess the relative severity (hospitalizations, intensive care unit [ICU] admissions, and deaths) of Gamma, Delta, and Omicron infections during 2021 relative to
Alpha, we used inverse probability treatment weighted Cox proportional hazard modeling. We also conducted a subanalysis among unvaccinated individuals, as assessed severity differed across VOCs and SDOHs.
RESULTS: We included 91,964 individuals infected with a SARS-CoV-2 VOC (
Alpha: n=20,487, 22.28%; Gamma: n=15,223, 16.55%; Delta: n=49,161, 53.46%; and Omicron: n=7093, 7.71%). Delta was associated with the most severe disease in terms of hospitalization, ICU admissions, and deaths (hospitalization: adjusted hazard ratio [aHR] 2.00, 95% CI 1.92-2.08; ICU: aHR 2.05, 95% CI 1.91-2.20; death: aHR 3.70, 95% CI 3.23-4.25 relative to
Alpha), followed generally by Gamma and then Omicron and
Alpha. The relative severity by VOC remained similar in the unvaccinated individual subanalysis, although the proportion of individuals infected with Delta and Omicron who were hospitalized was 2 times higher in those unvaccinated than in those fully vaccinated. Regarding SDOHs, the proportion of hospitalized individuals was higher in areas with lower income across all VOCs, whereas among Alpha and Gamma infections, 2 VOCs that cocirculated, differential distributions of hospitalizations were found among racially minoritized groups.
CONCLUSIONS: Our study provides robust severity estimates for all VOCs during the COVID-19 pandemic in British Columbia, Canada. Relative to
Alpha, we found Delta to be the most severe, followed by Gamma and Omicron. This study highlights the importance of targeted testing and sequencing to ensure timely detection and accurate estimation of severity in emerging variants. It further sheds light on the importance of vaccination coverage and SDOHs in the context of pandemic preparedness to support the prioritization of allocation for resource-constrained or minoritized groups.