Novavax announcement that their vaccine has high efficacy

This article was published on
March 12, 2021

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Novavax have published a press release stating that their COVID-19 vaccine candidate has shown high levels of efficacy against original and variant COVID-19 strains in United Kingdom and South Africa Trials.

Novavax have published a press release stating that their COVID-19 vaccine candidate has shown high levels of efficacy against original and variant COVID-19 strains in United Kingdom and South Africa Trials.


What our experts say

Context and background


Media briefing

Media Release

Expert Comments: 

Prof Lawrence Young

Further evidence that the South African virus variant is partially resistant to current vaccines. The Novavax protein-based vaccine is very effective against infection with the original virus variant (96.4% against symptomatic disease) with slightly reduced efficacy against the UK variant (B.1.1.7). However, the overall efficacy of this vaccine against the B.1.351 South African variant is significantly reduced at 48.6% – increasing to 55.4% if HIV-positive participants are excluded. This study supports the need for modifying existing vaccines to provide better protection. Moderna have recently announced the production of a variant-specific vaccine that incorporates the spike gene from the South African variant which will be tested in phase I clinical trials as a booster or primary vaccine – either alone or in combination with the original vaccine. And regulators, including the UK’s MHRA, have confirmed a fast-track process for approval of these modified vaccines. Vaccine manufacturers would need to provide robust evidence that the modified vaccine produces an immune response, but time-consuming clinical studies that do not add to the regulatory understanding of a vaccines safety, quality or effectiveness would not be needed. This is because researchers are now better able to measure protection by looking at antibodies in the blood following vaccination, reducing the need to wait and see whether or not people in a trial become infected with the disease. This would significantly reduce the length of time taken for the modified vaccine to be ready for use.

Dr Simon Clarke

The Novavax Covid-19 vaccine appears to be highly effective against the original versions of the coronavirus, but they’re not causing many infections in the UK nowadays.  To describe its effectiveness on variants as encouraging doesn’t tell the full story.  While this vaccine still shows decent efficacy against the ‘Kent’ variant, which is now predominant in the UK, its potency has been blunted against the ‘South African’ variant, which health authorities in the UK are desperately trying to supress, by over 40%.

The Government is taking a ‘glass half-full’ approach to these results, but we need to be mindful about the empty part of the glass which could cause serious problems if the public becomes more complacent about other measures of disease control with vaccination.  The UK’s rollout of vaccines could lead to a situation later this autumn where the ‘Kent’ variant has been largely wiped out, leaving a substantial number of people susceptible to novel variants like that from South Africa, or maybe even versions which we are currently unaware of.

Prof Paul Heath

These are enormously exciting findings and confirm the results of the earlier interim analysis. This is a highly effective and safe COVID-19 vaccine and one that is effective against the important UK variant. This wonderful news is a tribute to the over 15,000 volunteers in our trial, to the dedication of the UK investigators and to the huge support of the NIHR.

Prof Daniel Altmann

It has always been clear that the ability of vaccine-induced immunity to cope with the loss of some immune recognition in variants is a function of how much protective headroom you have to start with.

In general, the current vaccines induce very high levels of neutralising antibody, so they can still give protection even with some drop-off against the variants. This is especially true for Novavax, which induces enormous levels of immunity.

Dr Michael Head

The Novavax announcement continues the stream of excellent news we’ve had about vaccines over the last few months. It’s a remarkable achievement to have so many candidates either already approved or showing such positive results ahead of an application to the regulators.

Novavax have also announced they will be contributing over 1 billion doses to the COVAX initiative. Low- and lower-middle income countries will benefit from this vaccine, but we do need to make sure that they can receive doses sooner rather than later.

One note of caution is the observed lower effectiveness against B.1.351 variant of concern, as first observed in South Africa. This shows the impact variants can have upon the pandemic response and thus is a strong argument for keeping cases as low as possible whilst the burden of COVID-19 is high. However, there is still a clear protective effect there in the Novavax trial, and data from across all the COVID-19 vaccines suggests that they will be hugely protective against severe illness from all variants, which is still an excellent outcome.


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