BioSpace: Meissa’s Intranasal COVID-19 Vaccine Uses Codon Deoptimization for Stronger Responses

Meissa Vaccines’ intranasal live attenuated chimeric virus-based vaccine for SARS-CoV-2 (and its variants) recently was cleared for Phase I trials, which will start at the end of March. Unlike other live attenuated virus vaccines, it employs codon deoptimization to evoke a stronger-than-usual immune response.


If approved, it holds the potential of providing several years of immunity for COVID-19, thus greatly easing the administration and manufacturing burden for what seems likely to be an endemic disease.


The vaccine, known as MV-014-212, is based on the company’s respiratory syncytial virus (RSV) vaccine, which has Fast Track designation. That vaccine currently is in Phase II trials, where it appears well-tolerated in adults and in children as young as 15 months.


“Live attenuated virus-based vaccines have, historically, provided longer-lasting immunity (than other vaccine delivery methods,” Marty Moore, Meissa's cofounder, CEO and codeveloper of the technology, told BioSpace.


Their ability to be administered in a single dose is a particular benefit during the COVID-19 pandemic, he said, and makes them especially attractive for difficult-to-vaccinate populations and in regions where ultra-cold freezers are uncommon.


“The challenge for a live attenuated vaccine is to ensure it is properly attenuated and therefore cannot cause disease by infection,” Moore said. In this case, “We removed the RSV surface proteins and replaced them with the SARS-CoV-2 Spike (S) protein,” increasing antigen expression and either decreasing or eliminating expression of the immune suppressors.


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