Background: We evaluated the immunogenicity and safety of a dose of NVX-CoV2705, a JN.1 subvariant SARS CoV-2 rS vaccine, in adults previously vaccinated with authorized/approved COVID-19 vaccines. Methods: Study 2019nCoV-315 is a Phase 3, open-label, single-arm study to evaluate the safety and immunogenicity of a single dose of NVX-CoV2705 in previously COVID-19 vaccinated adult participants ≥18 years of age in the United States. Participants received one dose of NVX-CoV2705. The primary immunogenicity endpoint was the geometric mean titer (GMT) of serum neutralizing antibodies (nAbs) against the SARS-CoV-2 Omicron JN.1 variant at Day 28 following study vaccination and seroresponse rate (SRR) in ID50 titers for the JN.1 subvariant assessed at Day 28 following study vaccination. Primary safety endpoints include local and systemic solicited adverse events (AEs) up to day 6 post-vaccination, unsolicited AEs up to day 28, and treatment-related MAAEs, AESIs, and SAEs through Day 180. Exploratory endpoints also provided additional data for circulating variants. Results: Between 14 October 2024 and 15 October 2024, 66 participants were screened and 60 enrolled. A total of 58 participants were included in the Per Protocol Analysis Set. GMTs increased from 138.6 (95% CI: 88.0–218.2) to 671.4 (95% CI: 4377.0–1031.6) from baseline to Day 28. In addition, GMTs increased ≥3.8‑fold (GMFR) from baseline (Day 0) to Day 28 for currently circulating or emerging Omicron subvariants JN.1, LP.8.1, KP.2, KP.3, KP.3.1.1, MC.1, XEC, MC.10.1, LF.7, LF.7.2.1, LF.7.7.2, NB.1.8.1, XFC, and XFG, with an acceptable safety profile after single dose vaccination. Discussion: A single dose of NVX-CoV2705 induced a rapid and robust anti–SARS-CoV-2 immune response against the Omicron JN.1 and other circulating variants and had an acceptable safety profile. ClinicalTrials.gov identifier: NCT06409663
Alves et al. (2025) studied this question.