Torán-Monserrat Pere, Lamonja-Vicente Noemí, Costa-Garrido Anna, Carrasco-Ribelles Lucía A, Quirant Bibiana, Boigues Marc, Molina Xaviera, Chacón Carla, Dacosta-Aguayo Rosalia, Arméstar Fernando, Martínez Cáceres Eva María, Prado Julia G, Violán Concepción
Unitat de Suport a la Recerca Metropolitana Nord, Institut Universitari d'Investigació en Atenció Primària Jordi Gol, Mare de Déu de Guadalupe, 2, Mataró, 08303, Spain, 34 7415338.
Germans Trias i Pujol Research Institute, Badalona, Spain.
JMIR Public Health Surveill. 2024 Nov 22;10:e56926. doi: 10.2196/56926.
As the vaccination campaign against COVID-19 progresses, it becomes crucial to comprehend the lasting effects of vaccination on safeguarding against new infections or reinfections.
This study aimed to assess the risk of new SARS-CoV-2 infections based on the number of vaccine doses, prior infections, and other clinical characteristics.
We defined a cohort of 800 health care workers in a 24-month study (March 2020 to December 2022) in northern Barcelona to determine new infections by SARS-CoV-2. We used extended Cox models, specifically Andersen-Gill (AG) and Prentice-Williams-Peterson, and we examined the risk of new infections. The AG model incorporated variables such as sex, age, job title, number of chronic conditions, vaccine doses, and prior infections. Additionally, 2 Prentice-Williams-Peterson models were adjusted, one for those individuals with no or 1 infection and another for those with 2 or 3 infections, both with the same covariates as the AG model.
The 800 participants (n=605, 75.6% women) received 1, 2, 3, and 4 doses of the vaccine. Compared to those who were unvaccinated, the number of vaccine doses significantly reduced (P<.001) the risk of infection by 66%, 81%, 89%, and 99%, respectively. Unit increase in the number of prior infections reduced the risk of infection by 75% (P<.001). When separating individuals by number of previous infections, risk was significantly reduced for those with no or 1 infection by 61% (P=.02), and by 88%, 93%, and 99% (P<.001) with 1, 2, 3, or 4 doses, respectively. In contrast, for those with 2 or 3 previous infections, the reduction was only significant with the fourth dose, at 98% (P<.001). The number of chronic diseases only increased the risk by 28%-31% (P<.001) for individuals with 0-1 previous infections.
The study suggests that both prior infections and vaccination status significantly contribute to SARS-CoV-2 immunity, supporting vaccine effectiveness in reducing risk of reinfection for up to 24 months after follow-up from the onset of the pandemic. These insights contribute to our understanding of long-term immunity dynamics and inform strategies for mitigating the impact of COVID-19.
随着针对新冠病毒的疫苗接种运动的推进，理解疫苗接种对预防新感染或再感染的长期影响变得至关重要。
本研究旨在根据疫苗接种剂量、既往感染情况和其他临床特征评估感染新型严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的风险。
在巴塞罗那北部进行的一项为期24个月（2020年3月至2022年12月）的研究中，我们定义了一个由800名医护人员组成的队列，以确定SARS-CoV-2的新感染情况。我们使用了扩展的考克斯模型，特别是安德森-吉尔（AG）模型和普伦蒂斯-威廉姆斯-彼得森模型，并研究了新感染的风险。AG模型纳入了性别、年龄、职位、慢性病数量、疫苗接种剂量和既往感染等变量。此外，还调整了2个普伦蒂斯-威廉姆斯-彼得森模型，一个针对未感染或仅有1次感染的个体，另一个针对有2次或3次感染的个体，两者的协变量与AG模型相同。
800名参与者（n = 605，75.6%为女性）接种了1、2、3和4剂疫苗。与未接种疫苗的人相比，疫苗接种剂量分别显著降低（P <.001）了66%、81%、89%和99%的感染风险。既往感染次数每增加一个单位，感染风险降低75%（P <.001）。按既往感染次数对个体进行分类时，未感染或仅有1次感染的个体的风险显著降低了61%（P = 0.02），接种1、2、3或4剂疫苗时分别降低了88%、93%和99%（P <.001）。相比之下，对于有2次或3次既往感染的个体，仅在接种第四剂疫苗时风险降低显著，为98%（P <.001）。慢性病数量仅使既往感染0 - 1次的个体的风险增加了28% - 31%（P <.001）。
该研究表明，既往感染和疫苗接种状态均对SARS-CoV-2免疫力有显著贡献，支持了疫苗在大流行开始后的随访长达24个月内降低再感染风险的有效性。这些见解有助于我们理解长期免疫动态，并为减轻新冠病毒影响的策略提供信息。
