Genomics For Dummies

Now that we know what proteins do and how they’re made, we can get into the good stuff! Let’s do a little something different today, and talk about how mRNA vaccines work.

And a little recap about the science before we start:

1. mRNA is a molecule that encodes instructions to help cells make proteins. Specifically, mRNA is produced during the process of DNA ‘transcription’ and consists of a string of 3-letter blocks (‘codons’). These codons are read during the process of ‘translation’ to produce a string of amino acids, that then fold into a 3-D structure to form a protein! More on these processes here.
2. Proteins are large complex molecules that play many critical roles in the body – they include antibodies, enzymes, hormones, and many more molecules. More on proteins here.

mRNA vaccines are a relatively new technology. The concept has been studied for decades but was never fully put into practice until the COVID-19 pandemic! The first mRNA vaccine to achieve full FDA approval in the states was Pfizer’s COVID-19 vaccine. Moderna was the 2nd.

The COVID-19 virus has a unique “spike protein” on its outside membrane, allowing our body to identify the virus as it enters our body and to mount an immune response. On detecting this spike protein, our body recognizes that we have been infected with COVID-19, and starts to produce specific antibodies to the virus to try and fight it off. These antibodies then stay dormant in the body for a certain length of time to ensure the body is ready to fight off the virus incase there is re-infection. This is why testing for COVID-19 antibody levels in the blood can tell us whether or not someone has been previously infected.

The Pfizer mRNA vaccine simply contains mRNA that codes for this unique spike protein. When a patient is injected with the mRNA vaccine, the mRNA gets delivered to their cells- their body follows the mRNA instructions to produce these spike proteins. As these proteins are produced, their body recognizes the spike protein as belonging to the COVID-19 virus and thinks it has been infected, triggering an immune response to rapidly produce antibodies to the COVID-19 infection. And voilà! Antibodies for life a defined length of time!

This is why the first 24-48 hours following the vaccine can make some people quite unwell, as their immune system is actived and the body rapidly rushes to create antibodies. But because the vaccine doesn’t actually contain the virus itself, once the antibodies have been created, people should return to feeling back to their normal selves.

Similar to when people are infected with COVID-19 and create antibodies, the antibodies created during response to the vaccine stay dormant in the body for a certain length of time and help prevent infection. Now, when the body is infected, the body already has antibodies (and does not have to go through the process of creating them) – the body can therefore fight off the virus much more quickly, minimizing the symptoms, duration, and long-term effects of COVID-19 infection. “Booster” vaccines can help maintain high COVID-19 antibody levels.

Of course, the COVID-19 vaccine triggers a huge immune response to help the body create antibodies. In rare cases, there have been reports of post-vaccine onset autoimmune diseases and myocarditis (inflammation of the lining of the heart). But it is important to remember that even COVID-19 infection would result in a big immune response as the body rushes to create antibodies, and there have been reports of these diseases with/ after the infection itself (in fact, there is a bigger risk of myocarditis after COVID-19 infection than after getting the vaccine). Everything in medicine is about weighing up the risks and benefits of treatments, and here, the benefits of the vaccine far outweigh the risks. ☺️

Here’s a helpful video of a quick visual about how the mRNA COVID-19 vaccine works-

PS: Other companies like Astra-Zeneca and Johnson & Johnson used more traditional vaccine technologies for their COVID-19 vaccines, like viral vectors and inactivated forms of the virus. Pfizer and Moderna’s COVID-19 vaccines are still the only mRNA vaccines approved by the FDA.