Novavax: How protein-based corona vaccines could change the pandemic

In contrast, the large-scale studies by Novavax and Clover have provided data. According to an unchecked pre-release from October 2021 the Novavax vaccination offered more than 90 percent protection against symptomatic Covid-19 disease in a study with 30,000 people. The investigation was completed in early 2021 – before the delta variant appeared and milder forms of the virus were in circulation.

Clover, on the other hand, reported slightly lower efficacy for its protein-based vaccine: 67 percent protection against symptomatic Covid-19 of any severity. But that number is likely underestimated because the vaccine was tested on populations struggling with more contagious strains of Sars-CoV-2, including the Delta and Mu variants. Both vaccines raised levels of antibodies which are comparable to those of the most effective mRNA vaccinations. So the results would show that making Covid-19 vaccines using proteins “isn’t an inferior approach just because it took longer,” said Ryan Spencer, managing director of Dynavax Technologies in Emeryville, California. His company makes the excipient, called an adjuvant, for the Clover vaccine.

Apparently fewer side effects than mRNA vaccines

The vaccinations are apparently safe too. None of the 50 or so protein-based Covid-19 vaccines currently undergoing clinical trials caused serious side effects. Even many of the reactions that typically occur with vaccinations with mRNA or viral vectors – including headache, fever, nausea, and chills – were far less common with the protein-based alternatives. In clinical trials of the vaccine by Taiwanese Medigen Vaccine Biologics Corporation in Taipei City, far less than one percent of people developed a fever.

“The safety profile is very similar to that of flu vaccines,” said Szu-Min Hsieh, an infectious disease specialist at the National Taiwan University Hospital in Taipei, who together with colleagues in October 2021 published the results of the phase II study. “That could take away a lot of people’s worries,” thinks Cindy Gay, an infectious disease doctor at the University of North Carolina School of Medicine at Chapel Hill, who co-directed the testing of the Novavax vaccine.

© Nik Spencer / Nature; Dolgin, E .: How protein-based COVID vaccines could change the pandemic. Nature 599, 2021; German processing: spectrum of science (excerpt)

Differences in design

Even if any of the protein-based vaccines were to succeed – both in terms of effectiveness and in terms of acceptance – there is no reason to assume that all such vaccines will be equally successful.

On the one hand, the form of the spike protein used varies greatly from product to product: some use individual proteins, others groups of three, some use the entire spike protein, others only a fragment. Some proteins float freely in water, others are packaged in nanoparticles. On the other hand, the proteins are also produced with different cell types. Novavax and Sanofi / GSK use the cells of a moth caterpillar for the synthesis (Spodoptera frugiperda); Clover and Medigen rely on egg cells from hamsters, which are often used in the biotechnology industry for the production of therapeutic antibodies. In addition, the manufacturers use very different adjuvants, each of which stimulates the immune system in its own way and can lead to different vaccine reactions.

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