Protein-based Vaccines Reduce COVID-19 Symptoms

After three and a half years after the SARS-CoV-2 betacoronavirus began infecting people, 183 separate vaccines have entered clinical development.

Given this unprecedented response by vaccine developers, it could easily be assumed that COVID-19 vaccines have revealed all there is to know.

However, in The Lancet Respiratory Medicine, Gustavo Dayan and colleagues report the results of a phase 3 efficacy trial of a bivalent protein-based SARS-CoV-2 vaccine, offering new insights into vaccine-mediated protection against COVID-19.

This peer-reviewed article was published on September 13, 2023, and reported that Sanofi-GSK's Vidprevtyn® bivalent variant, a protein-based vaccine, conferred heterologous protection against symptomatic (symptoms) SARS-CoV-2 infection in the epidemiological context of the circulating contemporary omicron variant.

This study in adults was conducted in eight countries and concluded that a protein-based vaccine targeting both the wild-type and Beta SARS-CoV-2 spike proteins is an estimated 75.1% effective against symptomatic COVID-19 among previously infected people.

And 30.9% effective among those never infected amid the Omicron variant period.

These findings suggest that vaccines developed with an antigen from a non-predominant strain could confer cross-protection against newly emergent SARS-CoV-2 variants and reduce COVID-19 symptoms.

The epidemiological context for this clinical trial is markedly different from that of trials conducted at the outset of the pandemic, wrote these researchers.

Furthermore, this study reported rare serious adverse events dissimilar to recent mRNA COVID-19 studies.

Immediate unsolicited adverse reactions within 30 min after any injection were reported by four (<0·1%) participants in the vaccine group and six (<0·1%) participants in the placebo group. 

In a reactogenicity subset with data, one or more serious adverse events occurred in 30 (0.5%) vaccine recipients and 26 (0.4%) placebo recipients.

No adverse event of special interest, serious adverse event, or death was deemed treatment-related.

There were no reported cases of thrombosis with thrombocytopenia syndrome, myocarditis, pericarditis, Bell's Palsy, Guillain–Barré syndrome, or other immune-mediated diseases.

Earlier this week, the U.S. Food and Drug Administration (FDA) took action approving and authorizing for emergency use updated mRNA COVID-19 vaccines formulated to more closely target currently circulating variants and to provide better protection against serious consequences of COVID-19, including hospitalization and death. 

"Vaccination remains critical to public health and continued protection against serious consequences of COVID-19, including hospitalization and death," commented Peter Marks, M.D., Ph.D., director of the FDA's Center for Biologics Evaluation and Research, in a press release on September 11, 2023.

The VidPrevtyn Beta vaccine has been recommended by the European Medicines Agency and in the U.K. as a booster in adults previously vaccinated with an mRNA or adenoviral vector COVID-19 vaccine. 

VidPrevtyn Beta is not available in the United States. However, the protein-based Novavax COVID-19 Vaccine Adjuvanted (Nuvaxovid™, CovoVax™, NVX-CoV2373) has been offered in the U.S.

Novavax Inc.'s vaccines are genetically engineered using three-dimensional nanostructures of recombinant proteins critical to disease pathogenesis. 

The funding for this study originated from Sanofi, a co-producer of the vaccine, the U.S. Biomedical Advanced Research and Development Authority, and the U.S. National Institute of Allergy and Infectious Diseases.