Novavax COVID-19 vaccine shows 89% efficacy and protects against new variants

Novavax COVID-19 vaccine

Date: 29th January 2021

Novavax, Inc. have announced their COVID-19 vaccine, NVX-CoV2373, has an efficacy of 89.3%, in a Phase 3 clinical trial conducted in the United Kingdom (UK).  It is the first vaccine to be shown to have a significant efficacy against the rapidly emerging new UK and South African variants of SARS-CoV-2.

Novavax, based in Gaitherburg, US, is a biotechnology company developing next-generation vaccines for serious infectious diseases.  NVX-CoV2373 is produced in insect cells, and was created using recombinant nanoparticles. It is adjuvanted with Novavax’s proprietary saponin-based Matrix-M™, which enhances the immune response.  It contains the full-length, prefusion spike protein of SARS-Cov-2, and is administered in two doses.

The UK phase 3 study, has enrolled more than 15,000 participants between 18-84 years of age, including 27% over the age of 65. The first interim analysis was based on 62 cases – 56 cases of COVID-19 were observed in the placebo group versus 6 cases observed in the NVX-CoV2373 group, demonstrating an efficacy of 89.3%.  Based on PCR strain analysis from a subgroup of the cases, the calculated efficacy against the original COVID-19 strain was 95.6% and 85.6% against the UK variant strain, referred to as SARS-CoV-2 VUI 202012/01, Variant of Concern 202012/01, VOC-202012/01, or lineage B.1.1.7.

In the South Africa Phase 2b clinical trial over 4,400 participants have been enrolled.  29 cases were observed in the placebo group and 15 in the vaccine group, demonstrating an efficacy of 60% in the HIV negative population of the study.  Sequencing data on a subgroup of the cases revealed that 92.6% were the South Africa escape variant, referred to as the 501.V2 variant, 20C/501Y.V2 or B.1.351 lineage.

How does NVX-CoV2373 compare with other vaccines?

As is the case for the Oxford/AstraZeneca vaccine, AZD1222, Novavax’s vaccine is stable at 2°C to 8°C, therefore the roll out of a vaccination programme should be more simple that with the Moderna and Pfizer/BioNTech vaccines.  It is also shipped in a ready-to-use liquid formulation that permits distribution using existing vaccine supply chain channels.

The efficacy of NVX-CoV2373 appears comparable with AZD1222, mRNA-1273 (Moderna) and BNT162b2 (Pfizer/BioNTech) although this is the first to be assessed against the new variants in a clinical trial.  Whilst it is encouraging that is offers high protection against the UK variant and has an efficacy of 60% against the 501.V2 variant, this will result in significantly less protection for the latter strain. With this in mind, Novavax plan to immediately begin clinical development on a vaccine specifically targeted to 501.V2.

Novavax states that the primary benefit of their adjuvanted platform is that it uses a very small amount of antigen, enabling the rapid creation and large-scale production of combination vaccine candidates that could potentially address multiple circulating strains of COVID-19.  Therefore, they are ideally placed to tackle newly emerging strains of COVID-19.

With the supply and availability of vaccines being a pressing issue at the moment, the news of a new effective, COVID-19 vaccine is a welcome announcement.  Novavax initiated a rolling submission to the United Kingdom’s regulatory agency, the MHRA, in mid-January, so it hoped that doses of the vaccine will delivered in the second half of the year if approved.


For more information please see the press release from Novavax