Abstract
BACKGROUND: The recombinant protein-based vaccine, NVX-CoV2373, demonstrated 89.7% efficacy against COVID-19 in a phase 3, randomized, observer-blinded, placebo-controlled trial in the United Kingdom. The protocol was amended to include a blinded crossover; data to the end of the placebo-controlled phase are reported.
METHODS: Adults aged 18-84 years received two doses of NVX-CoV2373 or placebo (1:1) and were monitored for virologically confirmed mild, moderate, or severe COVID-19 (onset from 7 days after second vaccination). Participants who seroconverted to immunoglobulin G (IgG) against the nucleocapsid protein and did not meet criteria for symptomatic COVID-19 were classified as having asymptomatic disease. Secondary outcomes included anti-spike (S) IgG responses, wild-type virus neutralization, and T-cell responses.
RESULTS: Of 15185 participants, 13989 remained in the per-protocol efficacy population (6989 NVX-CoV2373, 7000 placebo). At a maximum of 7.5 months (median, 4.5 months) postvaccination, there were 24 cases of COVID-19 among NVX-CoV2373 recipients and 134 cases among placebo recipients, a vaccine efficacy of 82.7% (95% CI: 73.3-88.8). Vaccine efficacy was 100% (17.9-100.0) against severe disease and 76.3% (57.4-86.8) against asymptomatic disease. High anti-S and neutralization responses to vaccination were evident, together with S-protein-specific induction of interferon-γ secretion in peripheral blood T cells. Incidence of serious adverse events and adverse events of special interest were similar between groups.
CONCLUSIONS: A two-dose regimen of NVX-CoV2373 conferred a high level of ongoing protection against asymptomatic, symptomatic, and severe COVID-19 through >6 months postvaccination. A gradual decrease of protection suggests that a booster dose may be indicated.
| Original language | English |
|---|---|
| Pages (from-to) | 398-407 |
| Number of pages | 10 |
| Journal | Clinical Infectious Diseases |
| Volume | 76 |
| Issue number | 3 |
| Early online date | 10 Oct 2022 |
| DOIs | |
| Publication status | Published - 1 Feb 2023 |
Bibliographical note
AcknowledgementsThe study and article were funded by Novavax. We would like to thank all the study participants for their commitment to this study. We also acknowledge the investigators and their study teams for their hard work and dedication. In addition, we would like to thank the National Institute for Health Research, representatives from the Department of Health and Social Care laboratories and
NHS Digital and the members of the UK Vaccine Task Force. Editorial support was provided by Kelly Cameron of Ashfield MedComms, an Inizio company
Funding
This work was funded by Novavax, and the sponsor had primary responsibility for study design, study vaccines, protocol development, study monitoring, data management, and statistical analyses. All authors reviewed and approved the manuscript before submission. LF reports a position as a prior full-time employee, now contractor to Novavax re-imbursed hourly for work performed on this study and in analyses and drafting this report. IC reports providing medical writing support for this work as an employee of Novavax
Keywords
- CoVID-19
- Immunogenicity
- Asymptomatic Infections
- SARS-CoV-2
- Vaccine efficacy
Access to Document
- Heath_etal_CID_Safety_And_Efficacy_VoR
© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.com