Question about the mRNA COVID vaccines

January 2, 2021 10:14 AM

The mRNA vaccines cause our bodies to produce a spike protein which triggers the production of antibodies that wipe out both the spike protein and COVID. My question is: Could this mechanism deplete a natural reservoir of protein-building machinery that our bodies might rely on later in life? Do we even know, given that there is no data on the long-term effects of mRNA vaccines?

If so, wouldn't it make more sense to consider non-mRNA vaccines if we're lucky enough to have the option and if we're not at the front of the line for the mRNA vaccine now? Really hoping someone with domain expertise on mRNA vaccines can weigh in. I'm not anti-vaccine by any means (I support making MMR vaccination more-or-less mandatory across all 50 states and globally), but I would like more information about the mRNA vaccine in order to make an informed decision about it.

posted by jtothes to Science & Nature (12 answers total)

>Could this mechanism deplete a natural reservoir of protein-building machinery that our bodies might rely on later in life?

A good question! Your body is making this stuff all the time. As long as you are not significantly malnourished I can’t see how it would be an issue.
posted by tchemgrrl at 10:23 AM on January 2, 2021 [7 favorites]

Could this mechanism deplete a natural reservoir of protein-building machinery that our bodies might rely on later in life?

This bit i can answer - No, almost definitely not. Our cells are constantly producing mRNA to make proteins, in order to function. And mRNA is not stable, so the vaccine mRNA will break down in the body after a time and thats it. It can't hang around long term, and "using up" cell machinery isn't a concern unless you have a serious issue already with cell function.

Source: Not a current scientist but studied a lot of cell function as part of my degree.
posted by stillnocturnal at 10:26 AM on January 2, 2021 [8 favorites]

The short answer to your above-the-fold question is no.

The long answer is that the vaccine mRNA -> protein process works the same as the our-own-mRNA -> protein process, which is happening constantly in [almost] all our cells. The mRNA degrades fairly quickly. The number of mRNA strings introduced by the vaccine is truly minuscule compared to the number of your own mRNA strings (for each and every protein that your own cells are manufacturing every moment). This is not using up any significant amount of bodily resources.
posted by heatherlogan at 10:26 AM on January 2, 2021 [7 favorites]

MRNA has been used in cancer treatment and vaccinations against allergies for just over a decade now, has been used in retail animal vaccines for a bit longer, and people have been doing human vaccine trials since the 90s that simply failed to produce immunity, so we have a lot more longterm data than you might have been aware of.
posted by bashing rocks together at 10:40 AM on January 2, 2021 [14 favorites]

Gonna also add: mRNA vaccines are new in the popular consciousness and for population level usage, but have been studied for decades. So while we wouldn't know the long term effects of this specific vaccine, I'm sure the previous studies have had the chance to see if such long term effects were common in mRNA vaccines.

However, we do know that some percentage of people can have some rough short term side effects from the mRNA vaccines, so that's something to know going in.

On the other hand, my understanding is both mRNA vaccines showed higher efficacy than Oxford Astrazeneca and Sinopham. But, the mRNA vaccines are more expensive per dose, and they have trickier handling requirements. So the vast majority of the world is probably going to get one of the non-mRNA ones.

On my part, I'm going to take the first vaccine I have access to--the possible medium and long term side effects of COVID19, even for my below 40 age, intimidate me a lot more than the potential side effects of vaccines that have been through clinical trials.
posted by foxfirefey at 10:47 AM on January 2, 2021 [7 favorites]

Here is a reference indicating that mRNA has a half-life of a few minutes to a few days in human cells. mRNA is degraded quite quickly and the cells have to continually manufacture new mRNA to replace it. The hardest part of designing an mRNA vaccine is getting it to last long enough to travel through your blood and get inside the cells. Once there it will produce the desired protein for a short time but quickly degrade.
posted by JackFlash at 10:57 AM on January 2, 2021 [4 favorites]

Whatever the vaccine does, getting an actual case of Covid is going to do the same--but way, way, way more of it. By several orders of magnitude at least.

The mRNA vaccines will cause the production of a relatively small amount of antibodies and other immune system products, yes. But having an actual case of Covid (or any active disease, really--even just a cold or the flu) will produce much, much more.

In fact, you probably know that many of the worst problems caused by Covid are caused precisely by an extremely overactive immune response. I don't know the exact numbers off the top of my head, but in round numbers this means an immune response something like millions or billions of times more than what is caused by the vaccine.

In short, in practical terms the problem you have outlined is nothing to worry about.

If anything, you will be saving your immune system a whole lot of work by getting a vaccine--whether mRNA or any of the others. If you had the choice and were trying to discriminate which is "best" you would certainly go for the one that is most effective in preventing any disease at all and/or serious/long-term disease. At this point the mRNA vaccines are far ahead of the other approved vaccines in this department--and thus, by the criterion you are worried about, by far the best.
posted by flug at 12:14 PM on January 2, 2021 [3 favorites]

Here is another study that indicates that the median half-life of mRNA in human cells is 10 hours. This means that within a day or two, all of the mRNA from the vaccine in your cells is gone. What is left are the proteins mimicking the virus assembled by the mRNA which provoke the immune response.
posted by JackFlash at 1:24 PM on January 2, 2021

One of the cool features of complex multicellular organisms is something called tissue homeostasis. This term refers to the ever-present turnover of living tissue - from stem cell to fully mature cell type - they all exist simultaneously in your body and are constantly maturing into fresh tissue and the old stuff dying "on purpose". If you start to look at lifeforms from the perspective of whether they have tissue homeostasis, it really changes your view of evolution (well, it did for me).
Tissue homeostasis is the source of the old saw that every molecule in your body is replaced within some number of years. I don't remember the number because the specific number is likely not meaningful anyway.
When you have an immune response, some of that very development is taking place - this time from a cell that happens to be able to smell the spike protein. It will proliferate, gaining strength to be able to produce a specific antiviral response to covid.
The key thing our bodies see to make immunological targets is information, not matter. The information contained in the vaccine is transmitted across generations of immune cells. The vaccine gives the immune cell the information that preps your system to be ready to fight this one like hell.
Most cell types in the body regenerate readily and over-and-over. The tissue lining your intestines turns over pretty fast, like a week or two. Some tissues end up in limited supply - two notable examples being egg cells in bodies with ovaries and thymic cells, which is a source of some, but not all, immune cells.
So you do lose immunity as you age, but there is nothing to suggest that taking the vaccine would increase that rate in any way.
posted by jjray at 1:45 PM on January 2, 2021 [4 favorites]

Nthing all the others about how the amount of protein production directed by the vaccine is miniscule on the grand scale of normal body functioning.

Another thing to think about is that the natural Covid virus would direct the body to make this spike protein too, as well as a multitude of other proteins and to make the body regenerate the virus so that this forced protein production and virus regeneration can continue for multiple cycles. To its péril, the human body can handle the extra direction from the virus very well.

Whereas the vaccine is a one shot* deal - there's only going to be a short period of spike protein production before the vaccine mrna degrades.

*OK well actually a two shot deal if one is properly vaccinated...
posted by Tandem Affinity at 2:06 PM on January 2, 2021 [3 favorites]

Could this mechanism deplete a natural reservoir of protein-building machinery that our bodies might rely on later in life?

I study all the kinds of RNA that are used to make protein for a living. Two things to know in addition to the good replies already upthread: first, every cell in your body is constantly making many different proteins all the time just to stay alive. And second, a lot of the molecular ingredients used to make proteins (and the proteins themselves) are routinely broken down into their component parts and recycled to make new stuff.
posted by deludingmyself at 6:10 PM on January 2, 2021 [5 favorites]

Yeah, proteins in your body are constantly being made and degraded, the spike protein is not even very large for a protein that human cells make, and an actual viral infection would do more or less the same thing (except even more so because the infection would then make more virus that would spread to other cells, unlike the vaccine which just makes the one protein and then stops).
posted by en forme de poire at 10:20 PM on January 2, 2021 [1 favorite]