Key Points

While the currently available mRNA vaccines are highly effective at inducing an immune response against Covid, they present challenges like the high amount of mRNA needed to produce them and the constantly evolving nature of the pathogen.

"The virus changes, moving the goal post, and updating the vaccine takes some time," said senior author Suresh Kuchipudi, chair of Infectious Diseases and Microbiology at the University of Pittsburgh School of Public Health.

To address these challenges, the researchers created a proof-of-concept Covid vaccine using what's known as a "trans-amplifying" mRNA platform.

In this approach, the mRNA is separated into two fragments -- the antigen sequence and the replicase sequence -- the latter of which can be produced in advance, saving crucial time in the event a new vaccine must be developed urgently and produced at scale.

In addition, the researchers analysed the spike-protein sequences of all known variants of the SARS-CoV-2 for commonalities, rendering what's known as a "consensus spike protein" as the basis for the vaccine's antigen.

In mice, the vaccine induced a robust immune response against many strains of SARS-CoV-2.

"This has the potential for more lasting immunity that would not require updating, because the vaccine has the potential to provide broad protection," said Kuchipudi.

"Additionally, this format requires an mRNA dose 40 times less than conventional vaccines, so this new approach significantly reduces the overall cost of the vaccine."

The study, published in the journal npj Vaccines could inform more efficient vaccine development for other constantly evolving RNA viruses with pandemic potential, Kuchipudi said.

"We hope to apply the principles of this lower-cost, broad-protection antigen design to pressing challenges like bird flu."

- IANS