Phase 2/3 Study Shows Robust Immunogenicity of NVX-CoV2601 in Vaccine-Naive Individuals with Prior SARS-CoV-2 Infection
A phase 2/3 open-label study demonstrates that a single dose of the monovalent XBB.1.5 vaccine, NVX-CoV2601, elicits robust immunogenicity in vaccine-naive individuals with prior SARS-CoV-2 infection, comparable to those previously vaccinated with mRNA vaccines. The study, involving participants across 30 US sites, found no new safety signals and supports the use of single doses of NVX-CoV2601 for immunity against SARS-CoV-2, regardless of prior vaccination history.
Variants of SARS-CoV-2 have evolved rapidly, necessitating updates to vaccine compositions. The WHO, European Medicines Agency, and US FDA recommended updating COVID-19 vaccines to a monovalent XBB.1.5 composition for the 2023–2024 season. NVX-CoV2601, based on the same rS protein technology as the authorized prototype NVX-CoV2373, was developed in response to this guidance.
The phase 2/3, open-label 2019nCoV-313 study evaluated the immunogenicity and safety of NVX-CoV2601 in two populations: previously vaccinated adults and vaccine-naive adults with prior SARS-CoV-2 infection. The study aimed to assess the noninferiority of nAb responses elicited by NVX-CoV2601 in vaccine-naive participants compared to vaccinated participants.
The study met its co-primary objectives, showing that NVX-CoV2601 elicited a noninferior nAb response in vaccine-naive participants compared to vaccinated participants. Robust increases in nAbs were observed in both groups, with a greater increase in the vaccine-naive group. The safety profile of NVX-CoV2601 was consistent with that of the prototype vaccine, NVX-CoV2373, with no new safety signals identified.
The findings support the use of single doses of NVX-CoV2601 to elicit immunity against SARS-CoV-2, regardless of prior vaccination history. The study highlights the importance of updating COVID-19 vaccines to align with predominantly circulating strains and supports recommendations for the spring 2024 vaccination campaign in vulnerable individuals.
A single dose of NVX-CoV2601 is effective in eliciting robust immunogenicity in vaccine-naive individuals with prior SARS-CoV-2 infection, offering a promising approach to COVID-19 vaccination amidst high population-wide seroprevalence.

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primary day-28 analysis of a phase 2/3 open-label study
medrxiv.org · Jan 15, 2023
The NVX-CoV2601 vaccine, targeting the XBB.1.5 SARS-CoV-2 variant, demonstrated robust immunogenicity and safety in a st...