Emerging Generation of mRNA Vaccines

What distinguishes it? Traditional mRNA vaccines are composed of messenger RNA containing the genetic instructions to produce Covid’s spike protein. Upon entering the body, this mRNA is translated into proteins using the same cell machinery that interprets our own messenger RNA.

In contrast, self-multiplying mRNA vaccines also contain a gene encoding the spike protein and viral genes that encode for replicase—an enzyme that acts as a photocopier. As a result, a single self-multiplying mRNA molecule can generate many more. The concept of a self-replicating vaccine may initially be disconcerting. However, it’s important to note that despite these vaccines deriving their self-multiplication capability from viral genes, they lack the information necessary to generate the virus itself. Therefore, saRNA vaccines cannot create new viruses. Similarly to mRNA, saRNA swiftly degrades within the body. Although it lasts longer than mRNA, it does not multiply indefinitely.

Japan authorized a new vaccine called LUNAR-COV19 in late November, based on trial results involving 16,000 individuals in Vietnam. Researchers recently disclosed an 800-person comparative study between LUNAR-COV19 and Comirnaty, Pfizer-BioNTech’s mRNA vaccine. Vaccinated individuals received either five micrograms of LUNAR-COV19 or 30 micrograms of Comirnaty as a fourth booster dose. While both vaccines caused predominantly mild and rapidly resolving reactions, a higher percentage of individuals developed antibodies following the self-multiplying mRNA vaccine. One month later, antibody rates against Omicron BA.4/5 were higher in LUNAR-COV19 recipients. This could indicate improved resilience.

The company has submitted for authorization in Europe and is developing a self-multiplying mRNA vaccine for seasonal and pandemic flu. Other firms are investigating whether self-multiplying mRNA could aid in treating unique genetic conditions by providing missing proteins. In tandem with global biotech CSL, Arcturus—the company that co-developed LUNAR-COV19—is creating self-multiplying mRNA to combat ornithine transcarbamylase deficiency, a rare and life-threatening genetic disorder. This surge in mRNA research brings the promise of improved vaccines and innovative treatments.