Novavax BA.1 booster data support COVID-19 vaccine strain switch, but bivalent fails to bring benefits

Novavax has generated phase 3 data to support a switch to its BA.1 variant COVID-19 vaccine. But with the original shot holding its own, and a bivalent version failing to bring benefits, the biotech is pushing the message that its existing adjuvanted recombinant protein vaccine remains viable.

As mRNA vaccines from Moderna and Pfizer have come to dominate the COVID-19 landscape, Novavax has tried to carve out a distinct space for its shot and make the case that its modality has benefits over the incumbent technology. Specifically, the biotech has touted the “very broad responses” in recipients of its vaccine against the ancestral strain at a time when its rivals are launching variant-specific updates.

Even so, Novavax, while continuing to tout the effectiveness of its original “prototype” vaccine, has run a phase 3 clinical trial of monovalent and bivalent shots adapted to the BA.1 omicron subvariant. Gregory Glenn, M.D., president of R&D, framed the data as affirmation of the original vaccine. 

“Today's results show that use of our prototype vaccine as a booster induces cross-reactive responses to a broad range of variants with the potential to protect against future strains. This is a hallmark of our vaccine technology and shows the suitability of our current prototype vaccine as a booster even as the COVID-19 landscape continues to evolve,” Glenn said in a statement.

The study found the monovalent BA.1 vaccine candidate, NVX-CoV2515, induced greater neutralizing responses than the prototype vaccine in people not previously exposed to COVID-19. Novavax said the hit on the primary strain-change endpoint will enable it to shift to a new variant vaccine “if necessary.” Pseudoneutralization responses found the new vaccine had no benefits against BA.5.

Novavax’s bivalent vaccine fared worse, failing to deliver benefits over either of the other shots. The biotech has previously expressed skepticism about the benefits of the approach, with Glenn telling investors at an event in September that the team was “not absolutely convinced that we need to go to the bivalent” while acknowledging that some customers may want the option.

The results could put Novavax at a disadvantage if customers want a bivalent option. But, with countries in parts of the world using monovalent boosters against ancestral SARS-CoV-2 and BA.1 this season, it may be able to find takers for another approach. The data leave Novavax’s core argument that its current shot works in an ever-evolving, variant-rich environment intact while giving it the option to switch to a BA.1 variant vaccine if needed.