Alves Katia, Kouassi Alex, Plested Joyce S, Kalkeri Raj, Smith Katherine, Kaba Muneer, Nelson Joy, Zhu Mingzhu, Cloney-Clark Shane, Cai Zhaohui, Mallory Raburn M, Noriega Fernando
Novavax, Inc., 700 Quince Orchard Road, Gaithersburg, MD 20878, USA.
Novavax, Inc., 700 Quince Orchard Road, Gaithersburg, MD 20878, USA.
Vaccine. 2025 May 10;55:127046. doi: 10.1016/j.vaccine.2025.127046. Epub 2025 Apr 2.
BACKGROUND: Most of the population has been infected with SARS-CoV-2 and, thus, is primed by natural exposure. As such, it was assessed whether a single dose of the monovalent XBB.1.5 vaccine, NVX-CoV2601, elicited a comparable immune response to XBB.1.5 in seropositive unvaccinated participants to that in previously vaccinated participants, thereby allowing the former to forego a two-dose primary series. METHODS: In this phase 2/3, open-label, single-arm study (2019nCoV-313/NCT05975060 [group 2]), vaccine-naive participants ≥18 years with previous SARS-CoV-2 infection received one dose of NVX-CoV2601. This analysis compared the 28-day immunogenicity and safety of NVX-CoV2601 in vaccine-naive and previously vaccinated (≥3 prior mRNA-based vaccines, from 2019nCoV-313 group 1) participants. Noninferiority of neutralizing antibody (nAb) response in vaccine-naive versus vaccinated participants was the primary objective. The day-28 geometric mean titer (GMT) ratio (GMTR) and seroresponse rate (SRR; percentage of participants with a ≥4-fold rise in antibody response from baseline) were measured, and safety was assessed. RESULTS: Of the participants enrolled from September 11 to November 15, 2023, per-protocol sets included 306/338 (90.5%) vaccine-naive and 309/332 (93.1%) vaccinated participants. At day 28, adjusted GMTs (95% CI) against XBB.1.5 in the vaccine-naive and vaccinated groups were 1491.5 (1277.5-1741.4) and 841.4 (723.9-978.0), respectively. The vaccine-naive-vaccinated nAb GMTR was 1.8 (95% CI 1.43-2.20) and SRRs were 74.3% and 64.3% for vaccine-naive and vaccinated participants, respectively (SRR difference: 10.0 [95% CI 2.6-17.4]). No new safety signals or events of special interest were reported. CONCLUSIONS: A single dose of NVX-CoV2601 in vaccine-naive participants with a history of SARS-CoV-2 infection elicited a robust neutralizing antibody response that was noninferior to that observed in vaccinated participants. The vaccine was well-tolerated. These data support the use of NVX-CoV2601 as a single dose, regardless of prior vaccination history. TRIAL REGISTRATION: NCT05975060.
背景：大多数人群已感染过严重急性呼吸综合征冠状病毒2（SARS-CoV-2），因此已通过自然暴露获得免疫。据此，研究人员评估了单剂量单价XBB.1.5疫苗NVX-CoV2601在未接种过疫苗但血清反应呈阳性的参与者中，是否能引发与既往接种过疫苗的参与者中相当的针对XBB.1.5的免疫反应，从而使前者无需接种两剂的基础免疫程序。 方法：在这项2/3期、开放标签、单臂研究（2019nCoV-313/NCT05975060[第2组]）中，年龄≥18岁且既往感染过SARS-CoV-2的未接种过疫苗的参与者接种了一剂NVX-CoV2601。本分析比较了NVX-CoV2601在未接种过疫苗和既往接种过疫苗（来自2019nCoV-313第1组，≥3剂基于mRNA的疫苗）的参与者中的28天免疫原性和安全性。未接种过疫苗的参与者与接种过疫苗的参与者中中和抗体（nAb）反应的非劣效性是主要目标。测量了第28天的几何平均滴度（GMT）比值（GMTR）和血清反应率（SRR；抗体反应较基线升高≥4倍的参与者百分比），并评估了安全性。 结果：在2023年9月11日至11月15日招募的参与者中，符合方案集包括306/338（90.5%）未接种过疫苗的参与者和309/332（93.1%）接种过疫苗的参与者。在第28天，未接种过疫苗组和接种过疫苗组针对XBB.1.5的调整后GMT（95%CI）分别为1491.5（1277.5 - 1741.4）和841.4（723.9 - 978.0）。未接种过疫苗组与接种过疫苗组的nAb GMTR为1.8（95%CI 1.43 - 2.20），未接种过疫苗和接种过疫苗的参与者的SRR分别为74.3%和64.3%（SRR差异：10.0[95%CI 2.6 - 17.4]）。未报告新的安全信号或特别关注的事件。 结论：在有SARS-CoV-2感染史的未接种过疫苗的参与者中，单剂量NVX-CoV2601引发了强大的中和抗体反应，不劣于在接种过疫苗的参与者中观察到的反应。该疫苗耐受性良好。这些数据支持无论既往接种史如何，均可将NVX-CoV2601作为单剂量使用。 试验注册号：NCT05975060。
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