COVID-19 vaccines don’t change your DNA – What you need to know before getting vaccinated

Vehicles line up at a recent drive-through COVID-19 vaccination clinic at the Hardin County Fairgrounds.

With vaccines to protect against COVID-19 now being administered, many have questions such as how they they work, how they were developed so quickly, and whether they are safe and effective.

There are currently two vaccines available for use in the U.S. One was created by biotech company Moderna, of Cambridge, Massachusetts, and the other by a collaboration of pharmaceutical company Pfizer, of New York City, and biotech company BioNTech, of Germany.

Both are what are called “mRNA vaccines,” and both were given “emergency use authorizations” or EUAs by the U.S. Food and Drug Administration.

So far, in Hardin County, only one vaccine brand has been administered – the Moderna vaccine.

It’s often heard that mRNA vaccines are a brand new type of vaccine, and that they have never been used in humans before. That is not exactly true, and is somewhat misleading.

mRNA vaccines have been researched since the 1980s, and the first successful use of mRNA vaccines was in mice in 1990.While mRNA vaccines haven’t yet been on the commercial market, nor approved for general use by physicians, they have been tested in humans for at least four infectious diseases -- rabies, influenza, cytomegalovirus and Zika.

The arrival of COVID-19 has caused a sense of urgency to get them into widespread production.

So how do they work?

First, a little biology, summarized from information from the U.S. Centers for Disease Control and Harvard Medical School:

Starting with a very broad overview of how our immune system works, an antigen is something foreign to our bodies that produces an immune response, such as a virus or bacteria. When an antigen invades our system, most of the time our immune system recognizes it doesn’t belong there and destroys it.

One of the many problems with COVID-19 is that it’s very new to humans, so many people’s immune systems don’t recognize it quickly enough before it gets a strong foothold and causes serious damage.

The ultimate goal of all vaccines is to give the immune system a kind of advance warning that an antigen may be coming, so as soon as the antigen arrives in your body, the immune system will recognize it and get quickly to work to destroy it. That is the same with traditional vaccines and mRNA vaccines.

Most of us remember from high school biology that DNA is the basic “blueprint” for our entire bodies, and is inside the nucleus of every cell in our bodies. Every one of us also have mRNA naturally in every single cell – our bodies produce it every day, and it is vital to our system’s function.

The “m” in mRNA stands for “messenger,” and our cells use mRNA to learn from our blue print – DNA – what is needed. The mRNA then goes out of the nucleus and sends messages that instruct our cells what to do to keep our systems going. The mRNA, after sending its message, is expressed out of the cell and eventually cleared from our system.

In fact, the virus that causes COVID-19 is called an mRNA virus, because it inserts its own mRNA into our cells and sends out its own signals; one being to replicate itself. Then those copies go out and infect other cells, making us sicker and sicker as virus particles overwhelm our systems.

Researchers realized that to fight a tiny invader such as an mRNA virus, which hijacks our cells to replicate itself, the best way is to get down on its level.

Over decades, they have developed a way to create a small piece of synthetic mRNA that can be injected as a vaccine, enter our cells, and signal to our cells to create special proteins. Those proteins look like the outside of the virus, but are not the virus.

Once those proteins are created, they leave our cells, are noticed by our immune system, and our immune system gets its advanced warning of what to be on the lookout for.

So, essentially mRNA vaccines signal to our cells to create an impostor. Something that looks, but does not in any way act, like the virus. In a way, it’s similar to police showing a picture of a bad guy for everyone to look out for – the picture lets people know who to look for, but the picture can’t harm anyone because it’s not really the bad guy.

The mRNA vaccine is actually much easier and faster to manufacture than traditional vaccines, and doesn’t contain any eggs, preservatives or latex. Neither the Moderna nor Pfizer vaccines used fetal cell lines in development or production.

The synthetic mRNA never comes in contact with or changes your basic blueprint, your DNA, and once it’s sent it’s message to send out the impostor proteins, it’s eventually expressed out of the cell and clears your body, just like the mRNA we all produce naturally.

Now, however, your immune system knows what to look for, and if the real virus enters your system, it gets to work destroying it.

Vaccine trials

The Moderna vaccine is intended to be given in two doses, 28 days apart, for maximum effectiveness. Before being given EUA by the FDA, the Moderna vaccine underwent a large, randomized, double-blind, placebo-controlled clinical trial that enrolled 30,420 participants from age 18 to 95.

According to the CDC, the Moderna vaccine was 94.1% effective at preventing laboratory-confirmed COVID-19 illness in people who received two doses.

Citing the trial results, The Wall Street Journal reported that the first dose provided around 80% to 90% efficacy after 28 days. Two weeks after the second shot, the efficacy had reached 94.1% – indicating that the first shot by itself likely provides a good deal of protection from COVID-19, although both doses are still recommended.

The CDC and Tennessee Department of Health said the trials also indicate that in those who were subsequently infected with the COVID-19 virus after receiving the vaccine, the severity of the disease was often very much reduced or asymptomatic.

For the CDC’s report on the Moderna vaccine, including reported side effects (which have been generally mild and short-lived), visit www.cdc.gov/mmwr/volumes/69/wr/mm695152e1.htm.

To see the state’s vaccination plan, or vaccine facts vs. fiction, visit covid19.tn.gov/covid-19-vaccines/.