Departments of Pediatrics, Baylor College of Medicine, Houston, TX, United States; Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States.
Department of Pediatrics and Medicine, Emory University School of Medicine, Atlanta, GA, United States.
Vaccine. 2019 Aug 23;37(36):5161-5170. doi: 10.1016/j.vaccine.2019.07.085. Epub 2019 Jul 30.
In response to the emergence of influenza viruses with pandemic potential, we evaluated a swine-origin influenza A/H3N2 variant (H3N2v) vaccine in children.
This multicenter phase II open-label study assessed the safety and immunogenicity of two doses, 21 days apart, of investigational unadjuvanted subvirion monovalent inactivated H3N2v vaccine administered via intramuscular injection. Children 6-35 months of age received 7.5mcg or 15mcg of hemagglutinin (HA)/dose; children 3-17 years of age received 15mcg HA/dose. Safety and reactogenicity were assessed by measuring the occurrence of solicited injection site and systemic reactions in the 7 days after each vaccination; adverse events were assessed for 42 days and serious adverse events for 7 months after the first vaccination. Immunogenicity was evaluated by measuring hemagglutination inhibition (HAI) and neutralizing (Neut) antibodies to H3N2v prior to and 21 days after each vaccination. Cross-reactivity against seasonal H3N2 strains was evaluated.
The H3N2v vaccine was well tolerated. Transient mild to moderate injection site tenderness, pain and erythema was observed, with the most commonly reported systemic reactogenicity being irritability in children 6-35 months, and headache and fatigue in children 9-17 years old. Children 6-35 months old, whether they received 7.5mcg or 15mcg/dose, had low HAI and Neut antibody responses after two doses compared to older children. Children under 9 years of age required two doses of vaccine to demonstrate a response, while 9-17 year olds responded well after one dose. Previous influenza vaccination and older age were associated with higher immune responses to H3N2v vaccine. Children 9-17 years of age also developed cross-reactive antibodies against recent seasonal H3N2 influenza viruses.
The H3N2v vaccine was safe and immunogenic in children and adolescents. Age-related increases in immunogenicity against H3N2v and seasonal H3N2 viruses were observed, suggesting prior priming via infection and/or immunization. Clinical trial registry: The trial is registered with clinicaltrial.gov: NCT02100436.
针对具有大流行潜力的流感病毒的出现，我们评估了一种猪源甲型 H3N2 变异（H3N2v）流感疫苗在儿童中的效果。
这项多中心 2 期、开放性标签研究评估了两种剂量、间隔 21 天的经肌肉注射给予的、未添加佐剂的亚单位单价灭活 H3N2v 候选疫苗的安全性和免疫原性。6-35 月龄儿童接受 7.5mcg 或 15mcg 的血凝素（HA）/剂量；3-17 岁儿童接受 15mcg HA/剂量。通过测量每次接种后 7 天内的注射部位和全身反应的发生来评估安全性和反应原性；接种后 42 天内评估不良事件，接种后 7 个月内评估严重不良事件。在每次接种前和接种后 21 天，通过测量针对 H3N2v 的血凝抑制（HAI）和中和（Neut）抗体来评估免疫原性。评估了针对季节性 H3N2 株的交叉反应性。
H3N2v 疫苗具有良好的耐受性。观察到短暂的轻度至中度注射部位压痛、疼痛和红斑，最常见的全身性反应原性是 6-35 月龄儿童的烦躁不安，9-17 岁儿童的头痛和疲劳。与年龄较大的儿童相比，6-35 月龄儿童无论接受 7.5mcg 还是 15mcg/dose，在接受两剂疫苗后 HAI 和 Neut 抗体反应较低。9 岁以下儿童需要接种两剂疫苗才能产生反应，而 9-17 岁儿童只需接种一剂即可产生良好的反应。既往流感疫苗接种和年龄较大与对 H3N2v 疫苗的更高免疫反应相关。9-17 岁儿童还针对最近的季节性 H3N2 流感病毒产生了交叉反应性抗体。
H3N2v 疫苗在儿童和青少年中安全且具有免疫原性。观察到针对 H3N2v 和季节性 H3N2 病毒的免疫原性随年龄增加而增加，这表明通过感染和/或免疫接种进行了先前的启动。临床试验注册：该试验在 clinicaltrial.gov 上注册：NCT02100436。
