Aguilar-Jimenez Wbeimar, Rodriguez-Perea Ana Lucia, Chvatal-Medina Mateo, Velilla Paula A, Zapata-Builes Wildeman, Monsalve-Escudero Laura M, Zapata-Cardona Maria I, Tabares-Guevara Jorge Humberto, Rincón Daniel S, Hernandez Juan C, Tabares Yulied, Lopez-Carvajal Liliana, Rugeles Maria T
Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia.
Grupo Infettare, Universidad Cooperativa de Colombia, Medellín, Colombia.
Front Immunol. 2024 Dec 23;15:1504935. doi: 10.3389/fimmu.2024.1504935. eCollection 2024.
Despite its proven effectiveness and safety, there are limited real-world data on CoronaVac's immunogenicity in children, especially in lower-income countries, particularly for SARS-CoV-2 variants. We present a real-world study evaluating CoronaVac's immunogenicity in Colombian children stratified by previous exposure to this virus.
89 children aged 3-11 years were enrolled (50 Non-Exposed and 39 Exposed). Saliva samples were collected every 15 days to monitor potential SARS-CoV-2 infection, and blood samples were taken at two and six months after vaccination, to evaluate immunogenicity. Total IgG and IgA antibodies were measured by ELISA, and neutralizing titers against B.1, Delta, Mu, and Omicron variants were assessed by plaque reduction assay. T-cells were stimulated with wild-type and Omicron peptide pools to analyze activation-induced markers, memory phenotype, cytotoxic molecules, and cytokine production by flow cytometry.
CoronaVac was well tolerated, with only 7.8% infection incidence in both Exposed and Non-Exposed groups. It elicits a robust humoral response through IgG, IgA, and neutralizing antibodies against all variants. Despite waning, most participants maintained neutralizing titers ≥20 over time. CoronaVac also induced a polyfunctional cellular response against various strains, albeit reduced against Omicron, regardless of prior exposure. This response, characterized by IFN-γ/TNF-α and cytotoxic molecule production, was more pronounced in CD4 than in CD8 T-cells and remained detectable even after 6 months.
CoronaVac induces robust humoral and cellular immune responses against various variants in children, suggesting cross-recognition. However, these responses diminish over time, particularly in the context of variants, indicating the need for booster doses.
尽管科兴新冠疫苗已被证明具有有效性和安全性，但关于其在儿童中的免疫原性的真实世界数据有限，尤其是在低收入国家，特别是针对新冠病毒变异株。我们开展了一项真实世界研究，评估科兴新冠疫苗在哥伦比亚儿童中的免疫原性，并根据他们此前是否接触过该病毒进行分层。
招募了89名3至11岁的儿童（50名未接触过病毒的儿童和39名接触过病毒的儿童）。每15天收集唾液样本以监测潜在的新冠病毒感染情况，并在接种疫苗后的两个月和六个月采集血样，以评估免疫原性。通过酶联免疫吸附测定法检测总IgG和IgA抗体，并通过蚀斑减少试验评估针对B.1、德尔塔、缪和奥密克戎变异株的中和滴度。用野生型和奥密克戎肽池刺激T细胞，通过流式细胞术分析激活诱导标志物、记忆表型、细胞毒性分子和细胞因子产生情况。
科兴新冠疫苗耐受性良好，接触过病毒和未接触过病毒的组感染发生率均仅为7.8%。它通过IgG、IgA以及针对所有变异株的中和抗体引发强烈的体液反应。尽管抗体水平有所下降，但大多数参与者随着时间推移中和滴度仍维持在≥20。科兴新冠疫苗还诱导了针对各种毒株的多功能细胞反应，尽管针对奥密克戎的反应有所减弱，且与之前是否接触过病毒无关。这种以产生干扰素-γ/肿瘤坏死因子-α和细胞毒性分子为特征的反应在CD4 T细胞中比在CD8 T细胞中更明显，甚至在6个月后仍可检测到。
科兴新冠疫苗可在儿童中诱导针对各种变异株的强烈体液和细胞免疫反应，表明存在交叉识别。然而，这些反应会随着时间推移而减弱，尤其是在面对变异株的情况下，这表明需要接种加强针。
