Clinical Trial Info

Evaluation of the Safety and Immunogenicity of a SARS-CoV-2 rS Nanoparticle Vaccine With/Without Matrix-M Adjuvant

Authored by

2019nCoV-101 is a 2-part, randomized, observer-blinded, placebo-controlled, Phase 1/2 trial. Part 1 (Phase 1) of the study is designed to evaluate the safety and immunogenicity of SARS-CoV-2 rS nanoparticle vaccine with or without Matrix-M adjuvant in 131 healthy participants ≥ 18 to 59 (inclusive) years of age at 2 sites in Australia.

An interim analysis of Part 1 safety and immunogenicity will be performed prior to optional expansion to Part 2.

Part 2 (Phase 2) of the study is designed to evaluate the immunogenicity, safety, and preliminary efficacy of a single construct of SARS-CoV-2 rS nanoparticle vaccine with Matrix-M adjuvant in up to 1,500 healthy participants ≥ 18 to 84 (inclusive) years of age at up to 40 sites across Australia and/or the United States.


PLOS Medicine published results for this clinical trial on October 1, 2021.

The trial was conducted at 9 sites in Australia and 8 sites in the United States. Participants in 2 age groups (aged 18 to 59 and 60 to 84 years) were randomly assigned to receive either 1 or 2 intramuscular doses of 5-μg or 25-μg NVX-CoV2373 or placebo, 21 days apart. Primary endpoints were immunoglobulin G (IgG) anti-spike protein response, 7-day solicited reactogenicity, and unsolicited adverse events. A key secondary endpoint was wild-type virus neutralizing antibody response. After enrollment, 1,288 participants were randomly assigned to 1 of 4 vaccine groups or placebo, with 1,283 participants administered at least 1 study treatment. Of these, 45% were older participants 60 to 84 years.


The study confirmed the phase 1 findings that the 2-dose regimen of 5-μg NVX-CoV2373 is highly immunogenic and well-tolerated in younger adults. In addition, in older adults, the 2-dose regimen of 5 μg was also well-tolerated and showed sufficient immunogenicity to support its use in late-phase efficacy studies.