NEW HAVEN, Conn. — COVID’s Omicron variant has proven to be the most contagious strain of the virus yet. Now, scientists at Yale University have developed a new vaccine that offers improved protection against two of its sub-variants.
This new vaccine, aptly named Omnivax, has shown promise in mouse trials in two studies. In comparison to current mRNA vaccines, Omnivax successfully increased the neutralizing antibody response against the BA.1 and BA.2.12.1 Omicron sub-variants among a group of pre-immunized mice. Against these two strains, antibody protection rose by 19 times and eight times, 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,” says senior author of both studies Sidi Chen, associate professor of genetics at Yale School of Medicine, in a university release. “We wanted to see if we could develop variant-specific vaccines that offer additional protection against emerging sub-variants.”
How does the new vaccine work?
These experimental vaccines make use of engineered lipid nanoparticles to deliver mRNA to cells with “instructions” on how to forge spike proteins out of mutating variants, which the coronavirus uses to infect host cells. When the body detects the presence of those foreign viral fragments, the immune system reacts by creating antibodies.
Over time, rapid mutations among spike proteins on the surface of the virus led to a procession of sub-variants — better equipped to evade the protection provided by earlier generations of mRNA vaccines, including the Moderna and Pfizer-BioNTech shots.
Researchers add that they can engineer lipid nanoparticle mRNA vaccines quite quickly. For example, the BA.1 sub-variant of Omicron first emerged around Thanksgiving 2021. By mid-December, Yale researchers had already developed a vaccine against the new strain. Although, to be fair, it took until February 2022 to complete efficacy tests on mice. Moreover, by March 2022, the BA.2 sub-variant had become the predominately circulating strain throughout most of the world.
Next, study authors examined whether the Omicron variant vaccine maintained its superiority over standard vaccines for BA.2. Sure enough, researchers report the new vaccine successfully produced an immune response against BA.2 stronger than standard shots, at least in mice.
“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,” Prof. Chen explains.
The world already needs a newer vaccine
Today, the dominant sub-variants of Omicron are the new BA.4 and BA.5 variants. Researchers have already begun testing a new vaccine candidate against these latest versions.
“We have a system in place to combat these emerging sub-variants, but we need to adjust the system to respond more quickly to emerging health threats,” Prof. Chen concludes.