The Food and Drug Administration’s (FDA) Committee of Independent Expert Advisers voted overwhelmingly last week to approve the Novavax NVX-CoV2373 two-dose covid-19 vaccine. 21 of the 22 members of the committee voted in favor, one abstained.
The recommendation is currently relevant only two basic doses of vaccination for adults and does not address the possible administration of a booster dose. It should be noted that the Food and Drug Administration is not obliged to follow the committee’s recommendations, but usually takes them into account. If approved by the FDA, the Center for Disease Control and Prevention (CDC) will need to approve its use prior to implementation.
Deciding on Novavax, which is already authorized in dozens of other countries, is not at all easy in the United States. The vaccine has certain advantages over currently used vaccines, but also several disadvantages.
In terms of composition, the new vaccine differs from existing mRNA-based vaccines used in Pfizer and Moderna vaccines, as well as vector technologies known from AstraZeneca or Johnson & Johnson vaccines.
Simply put, it is designed according to a more traditional recipe – it is based on protein subunits. In general, the protein subunit vaccine design is tried and tested; It is used, for example, in vaccines against influenza, pertussis and meningococcal infection.
The vaccine therefore delivers SARS-CoV-2 coronavirus protein to spike cells along with an adjuvant, which is an ingredient used to boost the immune response. In this case, the adjuvant is derived from saponin compounds found in the Chilean soap tree that have previously been used in FDA-approved vaccines. Novavax also has a storage advantage over mRNA vaccines – it does not need to be stored frozen, but can be stored refrigerated.
Why another vaccine?
After more than two years of pandemics, mRNA vaccines are readily available in the United States, so most people who want to get vaccinated are already vaccinated. This raises the key question of what role the Novavax vaccine has yet to play and whether, given the availability of other vaccines, it deserves “emergency use” authorization.
Pharmaceutical company intends to target in particular those who do not trust relatively new mRNA vaccines. They believe that they could be persuaded to be vaccinated if they are offered an alternative that is perceived as more conventional.
“For those who are not fully vaccinated and are waiting for another option, a multi-stakeholder vaccination platform – including regulators, doctors and the public – can help alleviate some of the challenges we face today.” Greg Poland, CEO of Mayo Vaccine Research Group, spoke before the committee on behalf of Novavax.
Novavax has good results, but …
The Novavax vaccine had solid efficacy estimates in a clinical study published in the New England Journal of Medicine in February. In a study with more than 29,000 participants, she reported against symptomatic covid-19 efficacy 90.4%. Additional data suggest that it is generally safe and well tolerated, however, there may be an association with rare cases of inflammation of the heart (myocarditis) that have also been observed with mRNA vaccines.
Crucially, however, the study was completed last year, relatively long before the delta and omicron mutations (with all their subvariant) occurred. It is therefore unclear how this vaccine will protect against the latest coronavirus variants.
The only member of the FDA abstaining was Bruce Gellin. “The data we heard and saw were impressive”he said, but added with one breath that it is not clear how effective vaccination with this substance will be against existing virus mutations. He stated that he did not want to vote against the vaccine, but due to limited data he would not vote.