Barbieri Elisa, Trinh Nhung T H, Di Chiara Costanza, Corrao Giovanni, Boracchini Riccardo, Rosa Ester, Liberati Cecilia, Donà Daniele, Lupattelli Angela, Giaquinto Carlo, Cantarutti Anna
Department for Women's and Children's Health, University of Padua, 35128 Padua, Italy.
Pharmacoepidemiology and Drug Safety Research Group, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway.
Vaccines (Basel). 2025 Jun 27;13(7):698. doi: 10.3390/vaccines13070698.
: The approval of mRNA-based vaccines for children and adolescents has contributed to global efforts to control the SARS-CoV-2 pandemic. While hybrid immunity-combining prior SARS-CoV-2 infection and vaccination-may offer enhanced protection, data on its effectiveness versus vaccine-induced immunity in the pediatric population are limited. : This retrospective matched cohort study used linked health data from Norwegian nationwide health registries and the Italian Pedianet network. The study included children and adolescents aged 5-14 years eligible for COVID-19 vaccination at the time of approval (May/September 2021 and November 2021/January 2022, respectively). Mono- and two-dose vaccination schedules were assessed, and hybrid immunity was defined as prior SARS-CoV-2 infection followed by vaccination within 12 months. Conditional Cox regression models were used to estimate hazard ratios (HRs) for SARS-CoV-2 infection risk, adjusting for sociodemographics, comorbidities, and healthcare utilization. : The study included 626,537 children and adolescents in Norway and 38,938 in Italy. A single dose of the vaccine did not reduce the risk of infection among SARS-CoV-2-naive individuals in Norway (HR: 1.05; 95% CI: 1.04-1.07), whereas it was associated with an 8% risk reduction in Italy (HR: 0.92; 95% CI: 0.88-0.96). Among individuals with a recent prior infection (within 12 months), vaccination was associated with a reduced risk of reinfection in Norway (HR: 0.10; 95% CI: 0.05-0.13), but not in Italy (HR: 1.22; 95% CI: 0.83-1.80), compared to no vaccination. Among those with prior infection, vaccination was associated with a significantly reduced risk of reinfection in Norway (HR = 0.10; 95% CI: 0.05-0.20), but not in Italy (HR = 0.55; 95% CI: 0.27-1.11). Hybrid immunity provided greater protection against (re-)infection compared to vaccine-induced immunity alone, with a 26% risk reduction observed in Norway (HR = 0.74; 95% CI = 0.47-0.1.16) and an 86% reduction in Italy (HR = 0.14; 95% CI = 0.09-0.21). : This analysis supports the effectiveness of SARS-CoV-2 vaccines in children, with hybrid immunity offering enhanced protection against reinfection. Given the waning effectiveness of vaccines over time, continued research and booster strategies are essential to sustain protection and mitigate transmission.
基于信使核糖核酸的疫苗被批准用于儿童和青少年，这推动了全球控制新冠疫情的努力。虽然混合免疫（即先前感染过新冠病毒并接种疫苗）可能提供更强的保护，但关于其在儿科人群中与疫苗诱导免疫相比的有效性数据有限。
这项回顾性匹配队列研究使用了挪威全国健康登记处和意大利儿科网络的关联健康数据。该研究纳入了在批准时（分别为2021年5月/9月和2021年11月/2022年1月）符合新冠疫苗接种条件的5至14岁儿童和青少年。评估了单剂量和两剂量的疫苗接种方案，混合免疫被定义为先前感染过新冠病毒并在12个月内接种疫苗。使用条件Cox回归模型估计新冠病毒感染风险的风险比（HR），并对社会人口统计学、合并症和医疗利用情况进行了调整。
该研究纳入了挪威的626,537名儿童和青少年以及意大利的38,938名儿童和青少年。在挪威，单剂量疫苗并未降低未感染过新冠病毒个体的感染风险（HR：1.05；95%置信区间：1.04 - 1.07），而在意大利，单剂量疫苗与感染风险降低8%相关（HR：0.92；95%置信区间：0.88 - 0.96）。在近期有过感染（12个月内）的个体中，与未接种疫苗相比，接种疫苗在挪威与再次感染风险降低相关（HR：0.10；95%置信区间：0.05 - 0.13），但在意大利并非如此（HR：1.22；95%置信区间：0.83 - 1.80）。在有过感染的人群中，接种疫苗在挪威与再次感染风险显著降低相关（HR = 0.10；95%置信区间：0.05 - 0.20），但在意大利并非如此（HR = 0.55；95%置信区间：0.27 - 1.11）。与单独的疫苗诱导免疫相比，混合免疫对（再）感染提供了更强的保护，在挪威观察到感染风险降低26%（HR = 0.74；95%置信区间 = 0.47 - 1.16），在意大利降低86%（HR = 0.14；95%置信区间 = 0.09 - 0.21）。
该分析支持了新冠疫苗在儿童中的有效性，混合免疫对再次感染提供了更强的保护。鉴于疫苗的有效性会随时间减弱，持续的研究和加强免疫策略对于维持保护和减轻传播至关重要。
