How mRNA-based Vaccines Have Changed the Vaccine Game

With the unprecedented speed of vaccine development amid the COVID-19 pandemic, questions have emerged regarding the future of vaccinology beyond the coronavirus. In a panel on vaccinology in the 21st century hosted by Noble Life Sciences, scientists discussed the vaccine platforms available to us now, the significance of mRNA vaccines, and the emergence of new combination vaccines.

Different Vaccine Platforms

There are a variety of existing vaccine platforms, and many have been used to formulate COVID-19 vaccines. These include: nucleic acid (DNA and RNA), virus-like particle, peptide, viral vector (replicating and non-replicating), recombinant protein, live-attenuated virus, and inactivated virus approaches, according to an article published in Nature journal (2020).

It is thought that some platforms may be better suited for certain populations. For example, mRNA vaccines may have the ability to streamline vaccination through one vaccine effective for both healthy and vulnerable populations. The mRNA vaccine developed by Pfizer and BioNTech known as BNT162b2 was found to be 95 percent effective, including in the elderly, in their Phase 3 study. 

This differs from the influenza vaccine, in which people older than 65 years of age are recommended to receive a high-dose flu shot, different from the general population, who receive one of the following: inactivated influenza vaccine, recombinant influenza vaccine, or live attenuated influenza vaccine, according to the Centers for Disease Control and Protection.

Significance of mRNA Vaccines

mRNA-based vaccines are different from traditional influenza vaccines, which inject subjects with dead virus or attenuated, or weakened, live viruses to generate an immune response. 

mRNA or messenger RNA vaccines deliver genetic instructions for cells to make antigens (spike proteins), after which the body activates antibodies to fight these antigens, inducing an immune response. This occurs without ever exposing a patient to the actual virus. mRNA-based vaccines are advantageous in that they can be developed and fine-tuned more quickly than more traditional vaccines.

 “The rapid deployment and approval of the mRNA-based vaccines to SARS CoV-2 provides a paradigm shift in vaccine development,”  explained Stephen Horrigan, PhD,  the Chief Scientific Officer of Noble Life Sciences. “The combination of direct viral sequencing, rapid vaccine production, and efficient preclinical testing for candidate selection holds the promise of this technology to address future outbreaks with a speed not previously possible.”

Because mRNA-based vaccination allows researchers to approach vaccinology from an immunological-based approach as opposed to an empirical or through an ‘isolate, inactivate or attenuate, and inject’ approach (as researchers in a study published in Vaccines (2019) journal put it.), researchers can analyze our individual immune responses to see what works and find patterns in certain populations.

“The more we learn, the more we must consider what our immunological responses are looking like,” shared panelist Spencer Stonier, PhD, director of Vaccines Pipeline, Emergent Biosolutions.

Combination Vaccines

By using the learnings on mRNA vaccines and their capabilities, researchers can explore the formulation of more combination vaccines. For example, a future vaccine could incorporate various antigens as protective immunogens in one vaccine.

For instance, at the University of Pennsylvania Perelman School of Medicine, Drew Weissman, MD, PhD, who researches mRNA vaccines shared that in a soon-to-be-published study, he was able to combine mRNA for 20 antigens for different diseases in the same vaccine.  

“All 20 elicited good responses in mice,” he explained in a JAMA (2020) article. ”In theory, it might one day be possible for children to get two shots that cover their more than 50 vaccinations.”

Authors in a review article believe that mRNA vaccines “can simultaneously target multiple antigens, and pathogens will have broad utility for a range of diseases, reduce the number and frequency of vaccinations, and alleviate healthcare worker burden.”