The Rise of mRNA Vaccines

mRNA, or long-term messenger ribonucleic acid, is a single-stranded biomolecule produced from DNA (deoxyribonucleic acid), which is the main genetic material for many living things1. Messenger RNA (mRNA) can reach the cytoplasm by passing through the cell nucleus and carrying the genetic information stored in the DNA to the organelle called ribosome that enables the synthesis of proteins1.

The application we call a vaccine involves injecting a weakened version of a virus as a whole or molecules containing parts of the virus into the body2. The body recognizes this foreign substance and quickly creates defence cells. If we get the virus while it is active, the viruses could reach millions in number and make us sick while our defence system builds up resistance – which is what we call “viral disease”2. However, when we introduce the virus in a weakened form or only with specific parts such as surface proteins, the virus cannot make us sick; however, our defence system can effectively recognize the virus2. Thus, if we are to catch the virus in the future, our defence system will already be ready and by rapidly multiplying the defence molecules called antibodies, it will destroy the foreign substance before the virus can multiply sufficiently and make us sick2.

Specifically compared with DNA as a therapeutic or specifically as a vaccine, mRNA offers strong safety advantages3. mRNA does not interact with the genome, as the technological basis of therapeutics and vaccines is characterized by great flexibility concerning production and application3. Any protein can be encoded and expressed by mRNA, allowing the development of prophylactic and therapeutic vaccines that fıght various diseases and proteins, such as infections and cancer3.

Figure: Crown appearance of SARS-CoV-2.

A cell cannot distinguish whether the mRNA is it’s own or whether it is a foreign mRNA4. mRNA, if present in the cell, can travel to the ribosome and be read there. mRNA in a vaccine contains information about the spike protein that gives SARS-CoV-2 and other coronaviruses their name and that famous crown appearance4. This mRNA is read in the cells of our body and converted into spear proteins4. These spear proteins are useless without the rest of the virus; they float in or out of the cell in a completely meaningless way4.  However, as soon as defence cells see these proteins, they perceive them as “foreign matter” and begin to produce defence molecules (antibodies)4. So, again, we’re able to recognize the disease before our body gets sick and suffers the awful symptoms associated with COVID-194.

Vaccine production using mRNA has been a long-researched technique; however, it is not easy to produce a vaccine and no vaccine produced in this way has been approved until now5. The reason for this is that our control at the level of genes has only reached a functional and meaningful dimension in the 21st century, rather than that vaccines produced with mRNA are not safe enough5. Normally it takes years for a vaccine to be produced; because, in our old technologies, scientists had to produce the virus or proteins from scratch under laboratory conditions6. This is an extremely time-consuming, very costly process; because, in large bioreactors, it takes years of effort. Therefore, it may take more than 10 years to produce a single vaccine6.

However, mRNA technology reduces this time considerably; because the “bioreactor” used in this method is not a man-made machine, but our cells. Using the internal mechanisms of the cell, it is faster and more efficient to produce proteins6.

References:

  1. Loftus, Peter, Jared Hopkins, and Bojan Pancevski. “Moderna and Pfizer are reinventing vaccines, starting with covid.” Wall Street Journal(2020).
  2. Nance, Kellie D., and Jordan L. Meier. “Modifications in an emergency: the role of N1-methylpseudouridine in COVID-19 vaccines.” ACS Central Science5 (2021): 748-756.
  3. Mahase, Elisabeth. “Covid-19: Vaccine candidate may be more than 90% effective, interim results indicate.” (2020).
  4. Jackson, Lisa A., et al. “An mRNA vaccine against SARS-CoV-2—preliminary report.” New England journal of medicine(2020).
  5. Thomas, Katie, David Gelles, and Carl Zimmer. “Pfizer’s early data shows vaccine is more than 90% effective.” The New York Times10 (2020).
  6. Loftus, Peter, and Gregory Zuckerman. “Inside Moderna: The Covid Vaccine Front‐​ Runner with No Track Record and an Unsparing CEO.” The Wall Street Journal(2020).

Figure Reference: Abumandour, Mohamed, et al. “A review of the First Outbreak of the 2019 Novel Coronaviruses (SARS-CoV-2, COVID-19) in Egypt.” Journal of Morphological Sciences Vol38 (2021): 266.

Inspector: Ranya DEMİR

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