Yale scientists have developed a new Omicron-specific mRNA vaccine that offers better protection over subvariants than standard mRNA vaccines, according to the university.
The new vaccine, called Omnivax, had a better antibody response against the BA.1 and BA.2.12.1 Omicron subvariants in pre-immunized mice by 19-fold and eight-fold, respectively.
“While standard mRNA vaccines still offer protection against infection from new variants, their effectiveness wanes over time and was compromised due to immune escaping mutations in emerging variants,” said Sidi Chen, associate professor of genetics at Yale School of Medicine and senior author of both studies. “We wanted to see if we could develop variant-specific vaccines that offer additional protection against emerging subvariants.”
The experimental vaccines use engineered lipid nanoparticles to deliver mRNA to cells with “instructions” to create spike proteins from mutating variants, which the virus uses to attach to and infect cells, according to the university. The rapid mutation of these spike proteins has blunted the protection offered by earlier mRNA vaccines developed by Moderna and Pfizer-BioNTech, according to the university.
Researchers say the engineered lipid nanoparticle mRNA vaccines can be created quickly. For example, a vaccine for the BA.1 subvariant that emerged in November was created by mid-December by Yale researchers. Testing the vaccine in mice, however, wasn’t completed until February.
“Although translating the new vaccine candidate from bench to bedside requires rigorous testing in human trials, these preclinical studies provide a comprehensive and unbiased evaluation of an Omicron-specific vaccine candidate, which will hopefully fuel the development of next-generation COVID vaccines,” Chen said.
With the rise of BA.4 and BA.5 variants, Yale researchers are now testing a new vaccine candidate against them in mice, according to the university.
“We have a system in place to combat these emerging subvariants, but we need to adjust the system to respond more quickly to emerging health threats,” Chen said.