You’ve probably heard about mRNA vaccines before, at least in terms of those that were made in the fight against COVID-19. Maybe you are very familiar with the molecular mechanisms of vaccines, or maybe you’re not quite sure about how these things work. Well, I’m here to provide a bit of explanation about mRNA vaccines specifically!
To start, I should probably let you know what mRNA actually is! mRNA, or messenger RNA, is (you guessed it!) a type of RNA. Now what is RNA? It’s a type of nucleic acid, a class of macromolecules made up of nitrogenous bases bound to sugar molecules and phosphate groups, collectively called nucleotides. DNA is another type of nucleic acid, but these two differ largely in that DNA (deoxyribonucleic acid) lacks a hydroxyl (-OH) group at Carbon 2 (shown below; 1), among other differences.
Source: https://www.geeksforgeeks.org/difference-between-dna-and-rna/
mRNA is transcribed from DNA in the nucleus of eukaryotic cells by a special enzyme called an RNA polymerase. mRNA transcripts are subject to processing and alterations that help facilitate their movement out of the nucleus and prevent their degradation, and prior to these modifications, they’re called heterogenous nuclear RNA or hnRNA (2). After exiting the nucleus and being modified, these mRNA transcripts bind to a special organelle called the ribosome (a moiety that is actually largely made of another type of RNA: ribosomal RNA, or rRNA). At the ribosome, the mRNA is translated into a protein via the subsequent addition of amino acids to a growing chain. This pattern, of DNA to RNA to protein, is referred to as the Central Dogma of Biology (3).
Now back to vaccines! Given what you now know about mRNA and how it is translated into proteins, why do you think scientists would choose to include mRNA in vaccines? If you guessed “to make proteins,” you’d be correct! mRNA vaccines contain mRNA transcripts for proteins found on the virus or bacteria that it is meant to target, which induces an immune response against the protein, and thus a similar immune response against the virus or bacteria containing that protein in the event of infection. In the case of COVID-19, the Pfizer and Moderna vaccines, both mRNA vaccines, target proteins on the SARS-CoV-2 virus so that your body is able to fight it if you’re ever infected (4).
Source: https://www.asbmb.org/asbmb-today/science/122020/covid-19-vaccines-focus-on-the-spike-protein-but-t
Since mRNA vaccines came into the spotlight during the COVID-19 pandemic, there has been some debate about the safety of such vaccines. However, overall, mRNA vaccines have been a useful tool in fighting a variety of diseases for many years, including COVID-19!
Works Cited
Science with Mandy 
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