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expert reaction to press release from Novavax announcing Phase III results for their COVID-19 vaccine candidate which demonstrated an 89.3% efficacy

Novavax have announced that their COVID-19 vaccine candidate has completed Phase III trials in the UK where it demonstrated an 89.3% efficacy.


Dr Gillies O’Bryan-Tear, Chair, Policy and Communications, Faculty of Pharmaceutical Medicine, said:

“The Faculty of Pharmaceutical Medicine (FPM) welcomes the release of the data from the interim analysis of the first Novavax COVID-19 vaccine Phase III trial. The vaccine was studied in over 20,000 patients across the UK and South Africa, and showed efficacy of 89% in the UK trial (56 cases on placebo and 6 on vaccine). Importantly, the timing of the trial overlapped the emergence of the “UK variant”, and over half the UK cases had this strain: the vaccine showed 86% efficacy in these patients. A quarter of the patients were over 65 years of age, and no serious safety signals were reported.

“This vaccine uses a novel nanoparticle technology in which the complete spike protein of SARS-CoV-2 is linked to a proprietary adjuvant, Matrix-M, which enhances the immune response. This is a more traditional approach to vaccine development than the mRNA and viral vector vaccines already approved: the GSK/Sanofi vaccine also uses a protein/adjuvant approach but failed to show sufficient immune responses and has been delayed.

“In a preliminary analysis of a smaller, Phase 2 study in South Africa, efficacy was also observed in protecting against the South Africa variant which was dominant by the time of the trial; the estimate of efficacy was lower (60%) because of fewer cases, but the confidence limits were broad and overlapped those of the larger study. Of interest, one third of the patients enrolled were positive for prior Covid-19 infection, suggesting that prior infection with the wild type virus may not completely protect against the new variant.

“Novavax has started a rolling submission to the MHRA, who will review the data and make a decision on whether to authorise the vaccine for use in the UK. The UK, which helped to fund the development and manufacturing, has ordered 60m doses of the vaccine, which will be manufactured in Stockton-on-Tees. Shipments are reported to be starting by April.

“This is yet more good news for the effort to develop a range of vaccines against Covid 19, and is the first clinical data suggesting efficacy against the current UK and South Africa variants.

“If needed, this technology can also be rapidly adapted, to address emerging strains. The consensus is that full scale clinical trials will not be needed to approve new versions of the various vaccines.”


Dr Al Edwards, Associate Professor in Biomedical Technology, University of Reading, said:

“With all the news about who is getting how much of three approved vaccines, the press release suggesting the Novavax COVID-19 vaccine is effective remains extremely good news. While we still await full trial results for detailed scrutiny in a peer-reviewed publication, the headline that “a subunit vaccine works” is in fact highly significant. Why? Because it’s made by a different process, and it triggers an immune response in a distinct way to the other vaccines, yet it still provides protection. The Novavax vaccine is a subunit vaccine, comprising biosynthetic protein formulated carefully to create an immune response. This differs greatly from RNA vaccines (Pfizer/Biontech and Moderna), and from viral vaccines (Oxford/AstraZeneca and Sputnik plus Sinopharm).

“This gives sound confirmation that the “spike” protein is an excellent target for vaccination. At the same time it expands the potential global capacity for COVID-19 manufacturing, because this type of vaccine can be made in different factories to RNA or viral vaccines. It’s also great news for vaccine developers, as it provides us with more tools for rapid vaccine discovery into the future. All vaccines require careful manufacturing, but the composition of the Novavax makes it arguably the simplest yet to manufacture. It is very amenable to creating more stable and easier to distribute vaccine products. A triumph of protein engineering and formulation science, it is made possible by decades of investment in biopharmaceutical manufacturing.

“Finally, it is also greatly reassuring that the timing of this trial gives us vital real-world data about protection against variants of concern with modified spike structure, in the UK and South Africa. The initial statement suggests that protection is still seen (although reduced from ~90% to ~50%) in South Africa against the variant with the most distinct spike structure identified so far. However, more data on variants remains vital because the numbers in the press release remain small. But remember that 50% protection was our original target for a useful vaccine, and is not a failure. And even if overall protection from infection does fall with a spike variant, disease could well be less severe for vaccinated individuals who will have more rapid T cell immunity alongside partial antibody protection, compared to no vaccine. Further details are eagerly awaited.”


Prof Paul Hunter, Professor in Medicine, The Norwich School of Medicine, University of East Anglia, said:

“Novavax announced the results of its trials of its COVID-19 vaccine on 28th January. The Novavax vaccine is a prefusion protein nanoparticle vaccine. This is a type of subunit vaccine that works somewhat differently to the other vaccines authorised in the UK. The Pfizer, Moderna and OxfordAZ vaccines work by tricking the bodies cells to manufacture the parts of the virus that then trigger the immune system. The Novovax vaccine, by contrast, is made up with proteins from the virus already attached to a carrier and these trigger the immune system directly. The vaccine also contains an adjuvant to help the vaccine stimulate a stronger immune response. It is not a living vaccine and is also stable at ordinary refrigeration temperatures. The trials being conducted use two injections.

“The information we currently have comes from a press release and so as yet we do not have access to the analyses underpinning these claims. We will have to await peer-review publication before we can be confident in these findings. Also these are not the final results and more data will undoubtedly be being collected to enable more exact estimates of vaccine efficacy. Overall the statements on efficacy look very promising and would place the Novavax vaccine up with the other vaccines.

“Of particular note was that the trials in both the UK and South Africa were run at a time when the English and South African variants were dominant in their respective countries and as such this is the first time that we would have clinical trial data of the effectiveness of any vaccine against a new variant of concern. The English study estimated that the efficacy of the vaccine to older variants of SARS-CoV-2 was 95.6% and 85.6% against the English variant. Whether or not this represents a real difference if efficacy in uncertain because, with the numbers presented, the confidence intervals for these two subgroups will be overlapping. The overall efficacy in the English study was 89.3%. The South African study suggests a somewhat lower efficacy at about 60%. Although lower efficacy than against other variants, this is still a worthwhile level of immunity.

“The finding that the efficacy against the English variant is similar to that for older variants is not that surprising as the key mutation in this variant N501Y is not thought to be an escape mutation (a mutation that reduces the effectiveness of immunity to inactivate the virus). Whereas the South African variant also has the E484K mutation which is thought to be an escape mutation and so would reduce the impact of a vaccine. These observations on the relative efficacy of the Novavax vaccine against the two new variants of concern, if confirmed after full publication of the trials results, have implications for other vaccines as in general they all use similar parts of the virus to trigger immunity. This statement provides reassurance that the efficacy of the currently available vaccines against the English variant will not be dramatically reduced. However, it does suggest that efficacy against the South African variant of other vaccines will be lower, though worthwhile protection will still be achieved and hopefully protection against more severe disease will be greater still.”


Prof Paul Heath, Chief Investigator of the UK Novavax Vaccine Trial and Professor of Paediatric Infectious Diseases at St George’s, University of London, said:

“These are enormously exciting findings and show that this is a highly effective and safe COVID-19 vaccine – importantly it also shows that this is a vaccine that is effective against the UK variant that has spread so quickly. 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.”


Steve Bates, Chief Executive of the BioIndsutry Association (BIA), said:

“This is an incredibly important development for the UK and the world in being able to tackle COVID-19. This announcement is down to the foresight and planning of the UK Government Vaccine Taskforce (VTF) with the UK playing a crucial role in the Novavax global clinical trial, with more than 15,000 UK citizens participating.

“In six months the VTF has built a diverse portfolio of vaccine candidates that includes established vaccine platforms with proven safety profiles such as Novavax and Valneva, and newer but clinically advanced platforms, including Oxford/AstraZeneca, Pfizer/BioNTech, Janssen and Moderna. This multitude of vaccines means the UK will be well placed to combat variants and ensures that we have the necessary supply to vaccinate the UK population.

“This work shows again the strength of the UK life sciences and biotech sector which has been at the forefront of finding solutions to the COVID-19 pandemic whether in vaccines, diagnostics and therapies as well as harnessing its incredible genomic capacity which is being used to full effect to spot new variants of the COVID-19 virus.”


Prof Peter Openshaw, Professor of Experimental Medicine at Imperial College London, said:

“The finding that the Novavax vaccine gives high levels of protection in the UK limb of the trial is excellent, suggesting that the strong antibody responses and T cell responses seen in the phase 1 studies are confirmed to be associated with protection against COVID-19 disease. The UK study enrolled 15,000 participants between 18-84 years of age, including 27% over the age of 65. This first interim analysis is based on 62 cases of COVID, of which 56 were in the placebo group and 6 cases in the vaccinees giving an estimate of vaccine efficacy of 89.3% (95% CI: 75.2 – 95.4). Notably, the new variant B.1.1.7 emerged during the trial and still seemed to be supressed.

“The rather lower level of protection (60%, 95% CI: 19.9 – 80.1) seen in South Africa is a concern, given that the triple mutant variant virus (including three mutations in the receptor binding domain (RBD) and multiple mutations outside the RBD), was widely circulating at that time. The press release hints that prior infection with earlier variants of SARS-CoV-2 may not completely protect against subsequent infection by the variant of concern, but that vaccination with NVX-CoV2373 did provide some protection.”



All our previous output on this subject can be seen at this weblink:



Declared Interests

Dr Gillies O’Bryan-Tear: “Former Head of Vaccine Clinical Development, GSK.  I am a pharmaceutical physician, semi-retired and have worked in a variety of fields, including oncology (cancer) drug development and vaccines development.  I have been appointed CMO of Scancell, a U.K. listed biotech Company which has a Covid-19 vaccine candidate in preclinical development.”

Prof Paul Heath: “Prof Heath is the principal investigator on the UK arm of the Novavax Phase III vaccine trials.”

None others received.

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