mRNA Vaccines and the Fight Against the Pandemic

Decoding the Jargon

The pandemic has changed the way we live our daily lives — and as more and more vaccines are administered, more worry towards life post-pandemic. To many people, learning about the mechanisms of vaccines can be, quite justifiably, overwhelming — and the COVID-19 pandemic isn’t helping to ease that anxiety. Currently, there are four different mechanisms for the COVID-19 vaccines: viral vectors, mRNA, a weakened or inactivated form of the virus, and a protein-based vaccine. It’s difficult to compare vaccines; in fact, it is inaccurate to do so. Three statistics need to be pointed out when describing these vaccines: The efficacy after the first and second dose, as well as their effectiveness against severe Sars-Cov-2 infection & hospitalization.

A vaccine’s efficacy is a controlled measure of how well the drug performs in ideal settings; it is also constrained by variability of environments and the variety of medical conditions in different regions around the world. Moreover, pharmaceutical companies tend to exclude statistics where the efficacy is low, likely being sought as outliers. The more realistic numbers to look at are the effectiveness rates against hospitalization and severe Sars-Cov-2 infection, since such data is being evaluated in a less controlled and more real-world setting.

How Does the Sars-Cov-2 Virus Attack the Human Body?

Sars-Cov-2 is the name of the virus that causes COVID-19. First, the coronavirus enters the body through the respiratory tract, in which it can then embed into basal cells of the lungs. Shuibing Chen, a stem cell biologist and Weill Cornell Medicine in New York City used lung cells to map what happens when the novel coronavirus enters the body; she discovered that the virus induces the production of cytokines. The cytokine storms can trigger a major immune response which can be fatal.

How the COVID-19 virus infects the body. Credit: Ayunda Sukma

The virus’ spike proteins bind to the ACE2 receptor of a host cell and gets englufed by the cell in a process called endocytosis. ACE2 receptors are found in nasopharynx, lung, stomach, small intestine, colon, bone marrow, spleen, liver, kidney, muscle, and brain cells. Evidently, as Gavriatopoulou and her colleagues outline, the most commonly affected organs due to COVID-19 seem to be the lungs and gastrointestinal tract, with a broad range of neurological symptoms related to sensory and motor function.

How the mRNA Vaccine Protects You?

Vaccines protect both yourself and those around you, which is why vaccinating a large portion of the population is vital to control the third wave and pandemic as a whole. As more people get vaccinated, herd immunity works to prevent the mass spread of the Sars-Cov-2 virus. All of the COVID-19 vaccines lower your chance of contracting the disease if you are exposed to the virus. In the rare cases that a vaccinated individual does contract COVID-19, symptoms have been evident to be much milder.

How the mRNA-based COVID-19 vaccines prepares your body for an infection. Credit: Ayunda Sukma

The mRNA vaccines available, Pfizer and Moderna, protect your body against Sars-Cov-2 by instructing immune cells in the body to synthesize, or make, the spike protein piece of the virus. Each immune cell breaks down and disposes of the instructions, the mRNA. The cell transports the protein to its surface, which is recognized by the immune system. Similar to the immune response as to when the body is fighting COVID-19, the immune system starts making antibodies to hook onto and break down the spike protein.

As with every vaccine, our bodies utilize memory B cells in the immune system that store the blueprint for synthesizing antibodies to fight future COVID-19 infections; this prevents serious and lethal symptoms of COVID-19.

How were the vaccines produced so quickly?

An associate professor in the Biochemistry and Biomedical Sciences Department at McMaster University in Canada, Dr. Matthew Miller, notes that the mRNA and viral vector mechanisms used in the COVID-19 vaccines “in fact […] had both already been developed in preclinical stages against MERS coronavirus, which is related to Sars-Cov-2.” Synthetic mRNA in treatments, a technology that has been shown promise in the immunology world with little support in the past, is seen in the Pfizer-BioNTech and Oxford-Moderna COVID-19 vaccines. The mRNA work at BioNTech is currently being looked after by the reasercher behind the decades of scientific research — Katalin Karikó.

Dr. Miller further outlines the possibilities of mRNA technology, including the treatment of cancers:

MM: “The nice thing about the [mRNA technology] is that it’s essentially plug-and-play meaning it’s very easy to adapt mRNA vaccines to code for other antigens of interest.”

MM: “…mRNA vaccines are also being tested for indications that we don’t typically think of. So some cancers in particular have very well known what we call tumor-associated antigens that can be targeted by vaccines […] I would say one final, really exciting, potential application of mRNA vaccines could be in the vaccination of young children presuming that the safety profile holds up in that population…”

Science Communication as a Strategy to Flatten the Curve

A mindset shown in highly vaccinated populations is the facade of a near-ending pandemic. Various regions of the world have been, and still are, battling major COVID-19 outbreaks in the past two months, including India, Sweden, and Brazil. After coming this far, it is important to maintain current control measures (masks, gloves, and sanitization) even with the increased rollout of vaccines; the COVID-19 pandemic will end when each individual does their part in keeping their community safe and when the vast majority of the population is vaccinated. Educating others on the vaccines and how to effectively stay safe ultimately reduces the risk of entering yet another wave.