Department of Epidemiology and Public Health, Sciensano, 1050 Brussels, Belgium.
Department of Public Health and Primary Care, Ugent, 9000 Gent, Belgium.
Viruses. 2022 Apr 13;14(4):802. doi: 10.3390/v14040802.
The objective of this study was to investigate the incidence and risk factors associated with COVID-19 vaccine breakthrough infections. We included all persons ≥18 years that had been fully vaccinated against COVID-19 for ≥14 days, between 1 February 2021 and 5 December 2021, in Belgium. The incidence of breakthrough infections (laboratory confirmed SARS-CoV-2-infections) was determined. Factors associated with breakthrough infections were analyzed using COX proportional hazard models. Among 8,062,600 fully vaccinated adults, we identified 373,070 breakthrough infections with an incidence of 11.2 (95%CI 11.2-11.3)/100 person years. Vaccination with Ad26.COV2.S (HR1.54, 95%CI 1.52-1.56) or ChAdOx1 (HR1.68, 95%CI 1.66-1.69) was associated with a higher risk of a breakthrough infection compared to BNT162b2, while mRNA-1273 was associated with a lower risk (HR0.68, 95%CI 0.67-0.69). A prior COVID-19-infection was protective against a breakthrough infection (HR0.23, 95%CI 0.23-0.24), as was an mRNA booster (HR0.44, 95%CI 0.43-0.45). During a breakthrough infection, those who had a prior COVID-19 infection were less likely to have COVID-19 symptoms of almost all types than naïve persons. We identified risk factors associated with breakthrough infections, such as vaccination with adenoviral-vector vaccines, which could help inform future decisions on booster vaccination strategies. A prior COVID-19 infection lowered the risk of breakthrough infections and of having symptoms, highlighting the protective effect of hybrid immunity.
本研究旨在调查 COVID-19 疫苗突破性感染的发生率和相关风险因素。我们纳入了 2021 年 2 月 1 日至 2021 年 12 月 5 日期间，18 岁以上、完全接种 COVID-19 疫苗且接种后≥14 天的人群。确定了突破性感染（实验室确诊的 SARS-CoV-2 感染）的发生率。使用 COX 比例风险模型分析与突破性感染相关的因素。在 8062600 名完全接种疫苗的成年人中，我们发现了 373070 例突破性感染，发病率为 11.2（95%CI 11.2-11.3）/100 人年。与 BNT162b2 相比，接种 Ad26.COV2.S（HR1.54，95%CI 1.52-1.56）或 ChAdOx1（HR1.68，95%CI 1.66-1.69）与突破性感染风险增加相关，而 mRNA-1273 与较低的风险相关（HR0.68，95%CI 0.67-0.69）。既往 COVID-19 感染对突破性感染具有保护作用（HR0.23，95%CI 0.23-0.24），mRNA 加强针也是如此（HR0.44，95%CI 0.43-0.45）。在突破性感染期间，与初次感染的人相比，有既往 COVID-19 感染的人几乎所有类型的 COVID-19 症状都较少。我们确定了与突破性感染相关的风险因素，例如接种腺病毒载体疫苗，这有助于为未来的加强针接种策略提供信息。既往 COVID-19 感染降低了突破性感染和出现症状的风险，突出了混合免疫的保护作用。
