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The Beginners Guide to COVID-19 mRNA Vaccines

Aug 17, 2021 10:30:00 AM / by Nancy Andon, MSc

Part 1: What is an mRNA Vaccine?

Arya-and-Subbu-04Aug2021_Part1-2-4Vaccination is one of the most successful public health initiatives in history. Vaccine-preventable diseases are at or near an all-time low. So why are some people so hesitant to receive the COVID-19 vaccine?

It turns out that vaccine hesitancy is as old as vaccination itself. The unknown can be scary, and while modern humans may live in the “Age of Information”, most of us realize that not all information is reliable. Fortunately, help is on the way! In this 2-part blog series, the experts at HemaCare break down precisely what a mRNA vaccine is and how it works to protect those who get it.

Often taking the mystery out of a topic helps people feel more comfortable with it, and the goal of this blog series is to do exactly that. To help illustrate how the COVID-19 mRNA vaccine works, HemaCare is featuring the drawings of a budding young scientist.

COVID-19 has had a devastating effect on all parts of our society. It’s important to realize that while children are less likely to become seriously ill, in some ways, they are even more impacted than adults because a significant portion of their childhood is being shaped by this pandemic. For those who experienced the loss of an important person in their lives, the impact is tragically obvious. But whether directly impacted or not, many children struggle to understand why this is happening, and the whole topic can seem mysterious and perhaps scary. Even some basic knowledge can help kids realize that COVID-19 is not insurmountable. With this in mind, HemaCare decided it would be valuable to feature a first-hand look at COVID-19 vaccines as seen through the eyes of a child.

Arya Krishnan is a grade-schooler with a talent for simplifying a complex subject. His father Subramaniam is a scientist, and Arya himself shows considerable talent in that direction. Going by the precept that a picture is worth a thousand words, his hand drawings are aimed at bringing people of all ages to a clearer understanding of what the COVID-19 vaccine is and how it triggers the human immune system.

Messenger RNA (mRNA) vaccines are a new type of vaccine, but the technology behind them has been established for over a decade. [1] They offer significant safety advantages over traditional vaccines. Conventional vaccines contain viral proteins, part of the virus, or a harmless form of the virus. mRNA vaccines do not contain any part of the virus. Instead, an mRNA vaccine consists of a set of instructions called messenger RNA that cells in our body can translate into a protein. After being translated, the body quickly degrades the mRNA. It does not come into contact with our DNA or interact with it in any way.

COVID-19 is caused by a virus known as SARS-CoV-2. In the case of the COVID-19 vaccine, the mRNA codes for a harmless piece of the SARS-CoV-2 spike protein; the protein that the intact virus uses to attach itself to cells and infect them. The engineered version of the spike protein cannot attach to cell surfaces.

COVID-19 Vaccine Blog 2-Image

Once the modified spike protein is made, specialized cells will recognize it as a pathogen, and an immune response is initiated. While scientists know that the body’s response to this isolated piece of spike protein is fundamentally different than the response to the virus itself (more on this in Part 2), there are still gaps in knowledge regarding how different immune cell populations react.

To help scientists better understand mRNA vaccine immune response, HemaCare is launching a COVID-19 vaccine time series. Cryopreserved plasma, serum, and PBMCs from healthy donors who have not been exposed to COVID-19 are collected prior to vaccination, 10-30 days post vaccination, and 10-30 days after the booster shot (when applicable). These matched sets of samples can provide valuable data on what type of immune cells are present at a given time, how durable the immune response is, and much more. These samples are also invaluable for helping researchers pin down differences between the immune response of recovered COVID-19 patients and healthy donors vaccinated against the disease.

Stay tuned for Part 2 of our blog series, in which we will discuss how the COVID-19 mRNA vaccines trigger disease immunity and protect immunized people who may be exposed to the real virus.


Schlake T., et al. Developing mRNA-vaccine technologies. RNA Biology. 9(11): 1319–1330. Nov 2012.

Topics: Cryopreservation, PBMCs, Serum, Plasma

Nancy Andon, MSc

Written by Nancy Andon, MSc

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