Clinical Pharmacology, Pharmacy, and Environmental Medicine, Department of Public Health, University of Southern Denmark, Odense, Denmark
Clinical Pharmacology, Pharmacy, and Environmental Medicine, Department of Public Health, University of Southern Denmark, Odense, Denmark.
BMJ. 2021 May 5;373:n1114. doi: 10.1136/bmj.n1114.
To assess rates of cardiovascular and haemostatic events in the first 28 days after vaccination with the Oxford-AstraZeneca vaccine ChAdOx1-S in Denmark and Norway and to compare them with rates observed in the general populations.
Population based cohort study.
Nationwide healthcare registers in Denmark and Norway.
All people aged 18-65 years who received a first vaccination with ChAdOx1-S from 9 February 2021 to 11 March 2021. The general populations of Denmark (2016-18) and Norway (2018-19) served as comparator cohorts.
Observed 28 day rates of hospital contacts for incident arterial events, venous thromboembolism, thrombocytopenia/coagulation disorders, and bleeding among vaccinated people compared with expected rates, based on national age and sex specific background rates from the general populations of the two countries.
The vaccinated cohorts comprised 148 792 people in Denmark (median age 45 years, 80% women) and 132 472 in Norway (median age 44 years, 78% women), who received their first dose of ChAdOx1-S. Among 281 264 people who received ChAdOx1-S, the standardised morbidity ratio for arterial events was 0.97 (95% confidence interval 0.77 to 1.20). 59 venous thromboembolic events were observed in the vaccinated cohort compared with 30 expected based on the incidence rates in the general population, corresponding to a standardised morbidity ratio of 1.97 (1.50 to 2.54) and 11 (5.6 to 17.0) excess events per 100 000 vaccinations. A higher than expected rate of cerebral venous thrombosis was observed: standardised morbidity ratio 20.25 (8.14 to 41.73); an excess of 2.5 (0.9 to 5.2) events per 100 000 vaccinations. The standardised morbidity ratio for any thrombocytopenia/coagulation disorders was 1.52 (0.97 to 2.25) and for any bleeding was 1.23 (0.97 to 1.55). 15 deaths were observed in the vaccine cohort compared with 44 expected.
Among recipients of ChAdOx1-S, increased rates of venous thromboembolic events, including cerebral venous thrombosis, were observed. For the remaining safety outcomes, results were largely reassuring, with slightly higher rates of thrombocytopenia/coagulation disorders and bleeding, which could be influenced by increased surveillance of vaccine recipients. The absolute risks of venous thromboembolic events were, however, small, and the findings should be interpreted in the light of the proven beneficial effects of the vaccine, the context of the given country, and the limitations to the generalisability of the study findings.
评估在丹麦和挪威接种牛津-阿斯利康 ChAdOx1-S 疫苗后 28 天内心血管和止血事件的发生率，并将其与一般人群中的观察到的发生率进行比较。
基于人群的队列研究。
丹麦和挪威的全国医疗保健登记处。
所有在 2021 年 2 月 9 日至 2021 年 3 月 11 日期间接种 ChAdOx1-S 第一针的 18-65 岁人群。丹麦（2016-18 年）和挪威（2018-19 年）的一般人群作为对照组。
与两国一般人群的年龄和性别特异性背景率相比，接种疫苗人群在 28 天内因动脉事件、静脉血栓栓塞、血小板减少/凝血障碍和出血而发生医院接触的观察到的发生率。
丹麦的接种队列包括 148792 人（中位数年龄 45 岁，80%为女性）和挪威的 132472 人（中位数年龄 44 岁，78%为女性），他们接种了第一剂 ChAdOx1-S。在 281264 名接种 ChAdOx1-S 的人中，动脉事件的标准化发病率为 0.97（95%置信区间 0.77 至 1.20）。与一般人群的发病率相比，接种疫苗的队列中观察到 59 例静脉血栓栓塞事件，预计为 30 例，相应的标准化发病率为 1.97（1.50 至 2.54）和 11 例（5.6 至 17.0）每 100000 次接种增加的事件。观察到脑静脉血栓形成的发生率高于预期：标准化发病率为 20.25（8.14 至 41.73）；每 100000 次接种增加 2.5（0.9 至 5.2）例事件。任何血小板减少/凝血障碍的标准化发病率为 1.52（0.97 至 2.25），任何出血的标准化发病率为 1.23（0.97 至 1.55）。与 44 例预期相比，疫苗接种队列中观察到 15 例死亡。
在接种 ChAdOx1-S 的人群中，观察到静脉血栓栓塞事件（包括脑静脉血栓形成）的发生率增加。对于其余的安全性结果，结果基本令人放心，血小板减少/凝血障碍和出血的发生率略高，这可能与疫苗接种者的监测增加有关。然而，静脉血栓栓塞事件的绝对风险很小，应根据疫苗的已证实的有益效果、特定国家的情况以及研究结果的普遍性的局限性来解释这些发现。
