Recently, many companies around the world have announced their vaccines aimed to target and hopefully quell the COVID-19 pandemic. Of these, one particular type of vaccine has garnered some attention: mRNA vaccines.
Most of the vaccines that are in widespread use up to this point, despite falling into several sub-categories, have consistently employed some portion of the pathogen against which they protect. Some might contain dead or weakened viruses; others use a small portion to represent the pathogen and trigger an immune response. In other words, vaccines facilitate the body's immune system in recognizing and defeating the pathogen without causing severe illnesses and reducing the risk of more grave side-effects. As such, the immune system, having familiarized itself with the virus, will be better at defending the body against future attacks from the same pathogen.
As the CDC notes, mRNA vaccines also use this strategy. However, they employ an innovative and distinct way of providing our bodies with portions of the pathogen. mRNA instructs our cells to produce specific proteins. The COVID-19 mRNA vaccines contain the mRNA that codes for part of the virus: the spike protein on the outer surface of the coronavirus, which is recognized by receptors on the human cells.
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According to the developers of the vaccine, the vaccine delivers the instructions for creating COVID-19’s spike proteins to our cells. The cells then produce the proteins. Our immune system detects this foreign substance (as our bodies do not have such proteins) and launches an immune response. Since these are just proteins, which have no real viral ability, our immune system can move on to manufacturing antibodies with little hindrance. Thus, if one were to get COVID-19, our immune system will readily move to target those proteins on the virus, denying them entrance to our cells. Hence, immunity is achieved. In addition, being only proteins, one cannot contract COVID-19 from this vaccine, though some symptoms are normal side-effects of most vaccines.
Rather than necessitating a time-consuming process of obtaining samples of the pathogen, experimenting and identifying the critical piece, and finally weakening or extracting some portion of the pathogen, mRNA vaccines only need the genetic sequence to make parts of the pathogen. Specific to COVID-19, once scientists in China fully identified the genetic sequence of the virus, the information was made public and companies working on mRNA vaccines could get to work immediately without any extra steps. What this process entails is the potential to – put simply – “plug-in” whatever relevant sequence of mRNA or DNA needed to design a particular vaccine. This approach can be effective for various other diseases, even cancer. At the end of 2020, this might be one positive amidst it all.