Najimi Nouhaila, Kadi Chaimae, Gaouzi Zainab, Dakka Nadia, El Hassani Rabii Ameziane, Seghrouchni Fouad, Bakri Youssef
Laboratory of Human Pathologies and Biology, Faculty of Sciences, Mohammed V University, Rabat, Morocco.
Mohammed VI University of Sciences and Health, Casablanca, Morocco.
Pan Afr Med J. 2025 Jun 20;51:53. doi: 10.11604/pamj.2025.51.53.46802. eCollection 2025.
assessing the seroprevalence and persistence of humoral immunity through population-based serological surveys is crucial for predicting reinfection risk and optimizing vaccination strategies. In Morocco, a mass vaccination campaign against SARS-CoV-2 has been launched to achieve herd immunity and reduce virus transmission. This study evaluated the humoral immune response to the BBIBP-CorV and ChAdOx1 nCoV-19 vaccines in healthy donors with varying doses and infection histories.
IgG levels were measured via Vircell COVID-19 ELISA, and NAb levels were assessed via the GenScript Surrogate Virus Neutralization Test (sVNT). The study included individuals with different vaccination doses and prior infection histories.
the third vaccine dose produced the highest IgG titers, while nonvaccinated individuals and those receiving two doses had lower levels. Prior SARS-CoV-2 infection led to increased antibody levels, suggesting that hybrid immunity offers prolonged protection. The highest NAb titers were observed in individuals receiving three doses, with 96% of previously noninfected individuals being positive for NAb. Risk factor analysis indicated that prior infection (OR = 8.64, 95% CI: 2.52-29.6, p < 0.001) and three doses (OR = 22.1, 95% CI: 2.74-178, p < 0.001) increased immunity.
hybrid immunity, involving prior infection and full vaccination, offers enhanced and longer-lasting protection. These results support the need for targeted vaccination strategies to optimize immunity and reduce the risk of adverse outcomes, especially in high-risk populations.
通过基于人群的血清学调查评估体液免疫的血清流行率和持久性，对于预测再感染风险和优化疫苗接种策略至关重要。在摩洛哥，已发起针对严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的大规模疫苗接种运动，以实现群体免疫并减少病毒传播。本研究评估了不同剂量和感染史的健康供体对BBIBP-CorV和ChAdOx1 nCoV-19疫苗的体液免疫反应。
通过Vircell COVID-19酶联免疫吸附测定法测量IgG水平，并通过金斯瑞替代病毒中和试验（sVNT）评估中和抗体（NAb）水平。该研究纳入了具有不同疫苗接种剂量和既往感染史的个体。
第三剂疫苗产生的IgG滴度最高，而未接种疫苗的个体和接种两剂的个体水平较低。既往SARS-CoV-2感染导致抗体水平升高，表明混合免疫提供了更长时间的保护。在接种三剂的个体中观察到最高的NAb滴度，96%既往未感染的个体NAb呈阳性。危险因素分析表明，既往感染（比值比[OR]=8.64，95%置信区间[CI]：2.52-29.6，p<0.001）和三剂疫苗（OR=22.1，95%CI：2.74-178，p<0.001）可增强免疫力。
既往感染和全程接种疫苗所形成的混合免疫提供了更强且更持久的保护。这些结果支持需要采取有针对性的疫苗接种策略来优化免疫力并降低不良后果的风险，尤其是在高危人群中。
