COVID-19 has infected about 80 million people and killed about 1.7 million people across the world. In this urgency, pharmaceutical companies across the world are trying to develop vaccines for COVID-19 virus, and some of those vaccines are already being used. However, conventional vaccines that use inactive or weakened pathogens are not effective against rapidly evolving COVID-19 virus. The solution scientists found was mRNA vaccine. Pharmaceutical companies such as Pfizer and Moderna have been using mRNA to develop COVID-19 vaccines.
How are conventional vaccines and mRNA vaccines different?
Conventional vaccines launch immune responses by injecting inactive or weakened versions of pathogens into our bodies. Or, Instead of injecting the virus itself, pieces of proteins made by the pathogen known as antigens can be injected into our bodies and this will still launch the immune response (known as protein subunit vaccines). Memory B and T cells will save the information of the pathogen and with that information, white blood cells will fight the pathogen more efficiently in future infections.
Image from: WHO
mRNA vaccines work in a different way. mRNA vaccines do not use the actual virus. Instead, mRNA vaccines use a RNA sequence that codes for spike proteins that COVID-19 virus has on the surface. Once they are introduced to our bodies, mRNA strands will give “instructions” to ribosomes and ribosomes will translate the code and synthesize spike proteins. These spike proteins will be recognized by the immune system in your body and will trigger immune responses.
Image from: THE CONVERSATION
What are the advantages of mRNA vaccines and what are some challenges?
What are the advantages?
First of all, mRNA vaccines are easy and cheap to develop. Conventional vaccines usually take years and need to go through complicated processes to be developed. However, mRNA vaccines can be developed much faster than conventional vaccines, which makes mRNA vaccines more advantageous for large outbreaks. Also, mRNA vaccines can be easily manufactured and their manufacturing method can be easily standardized, which means that they are much cheaper to manufacture than traditional vaccines.
Moreover, while conventional vaccine development may be dangerous because it is dealing with actual viruses, mRNA vaccines are not made with or they do not deal with actual viruses, which means that they are much safer and non-infectious.
mRNA vaccines are advantageous especially for pathogens that mutate like COVID-19. Even though pathogens mutate and their sequences change, scientists can easily modify the RNA sequence whenever mutants appear.
What are the challenges?
Transportations and storage of the vaccine would be the most challenging part of mRNA vaccine development. Because naked mRNA particles are really unstable and are easily destroyed, there needs to be a way to safely store the vaccine preventing it from degrading.
Another challenge would be that its safety is not hundred percent guaranteed. Conventionally, new vaccines need to go over multiple clinical demonstrations before being used and standardized, which takes more than years. However, because COVID-19 is rapidly spreading across the world, FDA, the Food and Drug Administration, approved mRNA vaccine even though the vaccine has not yet gone over enough clinical demonstrations. This means that there might be side effects or risks that we yet do not know.
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