Although we have come to associate COVID-19 with many negatives- school closures, quarantine, social distancing, and travel restrictions to name a few- it has also provided a boost for science, particularly in the area of vaccine research. The pandemic of historical proportions has triggered a global race to develop a vaccine against the virus.
The development of a new vaccine typically takes 10-15 years, a luxury the world can ill afford right now. So companies around the world are racing to find a solution in record time. This has led to the development of an entirely new type of vaccine called mRNA or messenger RNA vaccine. mRNA vaccines are not a new concept; they have been known for a few decades but have not been developed seriously until now. mRNAs are tiny pieces of genetic code that tell cells in our bodies to make a protein.
The two companies at the forefront of vaccine development, Pfizer and Moderna, are both using mRNAs to develop a vaccine. They both use synthetic mRNA containing the SARS-CoV-2 spike protein that is characteristic of the novel coronavirus. When a vaccine containing this mRNA with the spike protein instructions is given to a person, it instructs the body to produce a small amount of the spike protein, which then triggers the immune system to start fighting it by producing protective antibodies. Once these antibodies are produced in the body, they stand ready to fight the real coronavirus when exposed to it in the future.
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| Mechanism of mRNA vaccine. Source: Pfizer |
Traditional vaccines require growing the actual virus in a lab, killing or inactivating it, injecting it into a carrier such as a bacteria or yeast, and then administering it into a healthy person. The presence of the virus, even in its dead form, triggers the immune response of the body to produce the antibodies necessary to fight the live virus. However, this type of vaccine takes years to grow and produce on large scale. It also requires vaccine development methods specific to each new virus. The mRNA vaccine, on the other hand, is a platform that once developed, can be easily modified to combat any new virus. It does not contain the actual virus, only instructions for producing the signature protein of the virus. Moreover, it does not require any manufacturing of biological matter in the lab, but can simply be designed on a computer once the specific spike protein of a new virus is identified. It is essentially like programming instructions, the actual manufacturing of the protein is done inside the human body. Hence it can leapfrog traditional vaccine development by many months or years. There are also other benefits to mRNA vaccines: since it does not contain any real virus and only a small part of the virus code, it should be safer and prevent serious infections that are sometimes seen with traditional vaccines.
It does not mean there are no risks or challenges with mRNA vaccines. Manipulating the immune system of a human body in any way can get tricky, as it is extremely complicated. The mRNA is also very fragile and inherently unstable, and requires extremely cold temperatures (as low of -94F in the case of the Pfizer mRNA) for storage. But the results from both Pfizer and Moderna vaccine trials, showing ~95% effectiveness against the coronavirus, are extremely promising and offer great hope, not only for a quick end to the pandemic but also for unlocking a new line of vaccines for the future. mRNA vaccines can be used to combat a variety of diseases from the flu to HIV, and even multiple diseases with the same vaccine. The pandemic, while bringing us to a new way of life on one hand, has also ushered in a new era in medicine.
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