Efficacy of NVX-CoV2373 Covid-19 Vaccine against the B.1.351 Variant

Background The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants threatens progress toward control of the coronavirus disease 2019 (Covid-19) pandemic. In a phase 1–2 trial involving healthy adults, the NVX-CoV2373 nanoparticle vaccine had an acceptable safety profil...

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Published in:New England Journal of Medicine 2021-05
Main Authors: Shinde, Vivek, Bhikha, Sutika, Hoosain, Zaheer, Archary, Moherndran, Bhorat, Qasim, Fairlie, Lee, Lalloo, Umesh, Mduduzi S.L. Masilela, Moodley, Dhayendre, Hanley, Sherika, Fouche, Leon, Louw, Cheryl, Tameris, Michele, Singh, Nishanta, Goga, Ameena, Dheda, Keertan, Grobbelaar, Coert, Kruger, Gertruida, Carrim-Ganey, Nazira, Baillie, Vicky, de Oliveira, Tulio, Anthonet Lombard Koen, Lombaard, Johan J, Mngqibisa, Rosie, As’ad E. Bhorat, Benadé, Gabriella, Lalloo, Natasha, Pitsi, Annah, Pieter-Louis Vollgraaff, Luabeya, Angelique, Esmail, Aliasgar, Petrick, Friedrich G, Oommen-Jose, Aylin, Foulkes, Sharne, Ahmed, Khatija, Thombrayil, Asha, Fries, Lou, Cloney-Clark, Shane, Zhu, Mingzhu, Bennett, Chijioke, Albert, Gary, Faust, Emmanuel, Plested, Joyce S, Robertson, Andreana, Neal, Susan, Cho, Iksung, Glenn, Greg M, Dubovsky, Filip, Madhi, Shabir A
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Language:English
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COVID-19 vaccines
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Summary:Background The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants threatens progress toward control of the coronavirus disease 2019 (Covid-19) pandemic. In a phase 1–2 trial involving healthy adults, the NVX-CoV2373 nanoparticle vaccine had an acceptable safety profile and was associated with strong neutralizing-antibody and antigen-specific polyfunctional CD4+ T-cell responses. Evaluation of vaccine efficacy was needed in a setting of ongoing SARS-CoV-2 transmission. Methods In this phase 2a–b trial in South Africa, we randomly assigned human immunodeficiency virus (HIV)–negative adults between the ages of 18 and 84 years or medically stable HIV-positive participants between the ages of 18 and 64 years in a 1:1 ratio to receive two doses of either the NVX-CoV2373 vaccine (5 μg of recombinant spike protein with 50 μg of Matrix-M1 adjuvant) or placebo. The primary end points were safety and vaccine efficacy against laboratory-confirmed symptomatic Covid-19 at 7 days or more after the second dose among participants without previous SARS-CoV-2 infection. Results Of 6324 participants who underwent screening, 4387 received at least one injection of vaccine or placebo. Approximately 30% of the participants were seropositive for SARS-CoV-2 at baseline. Among 2684 baseline seronegative participants (94% HIV-negative and 6% HIV-positive), predominantly mild-to-moderate Covid-19 developed in 15 participants in the vaccine group and in 29 in the placebo group (vaccine efficacy, 49.4%; 95% confidence interval [CI], 6.1 to 72.8). Vaccine efficacy among HIV-negative participants was 60.1% (95% CI, 19.9 to 80.1). Of 41 sequenced isolates, 38 (92.7%) were the B.1.351 variant. Post hoc vaccine efficacy against B.1.351 was 51.0% (95% CI, −0.6 to 76.2) among the HIV-negative participants. Preliminary local and systemic reactogenicity events were more common in the vaccine group; serious adverse events were rare in both groups. Conclusions The NVX-CoV2373 vaccine was efficacious in preventing Covid-19, with higher vaccine efficacy observed among HIV-negative participants. Most infections were caused by the B.1.351 variant. (Funded by Novavax and the Bill and Melinda Gates Foundation; ClinicalTrials.gov number, NCT04533399.)
DOI:10.1056/NEJMoa2103055