From the frenzy of people who object to the use of mRNA technology in vaccines, one might conclude that genetic material from space aliens was being injected into people in some grand plan to convert humans into giant tadpoles. Although little from the anti-vaxxer camp makes sense on a good day, this particular fear becomes nonsensical and silly once the science is understood. One way to do this is by comparing the quantity and properties of the mRNA in the vaccine with that generated in a viral infection.
What is mRNA and what is its function?
mRNA stands for messenger RNA, a short-lived yet essential biomolecule found in all living organisms. It’s vital for life because it shuttles instructions from DNA to ribosomes, where protein synthesis occurs, providing cells with the information needed to build proteins from amino acids. Without mRNA, protein synthesis would come to a screeching halt, preventing cells from performing essential functions or even reproducing. Simply put, life without mRNA would be impossible.
Why the fear?
- Fear of Genetic Alteration
Some claim that mRNA vaccines could alter their DNA by integrating foreign genetic material into their genome. In reality, this is impossible. DNA integration requires an enzyme called integrase, found in certain viruses like HIV, which can insert viral genes into human DNA. Without integrase, mRNA cannot alter our DNA.
By contrast, HIV requires integrase to replicate. The enzyme "cuts" host DNA in specific regions, allowing foreign material to be inserted and "stitched" into our genome. This ability is what makes HIV so difficult to cure. Once someone is infected, their genome contains a DNA sequence that instructs certain immune cells to produce new HIV particles, effectively turning the body into a factory for the virus. In a sense, you aren't you anymore.
- Persistence of vaccine mRNA
RNA is chemically and enzymatically unstable making it short-lived, something I've explained in the past. The explanation involves a fundamental process in organic chemistry called "neighboring group participation" arising from the presence of a hydroxyl group in the 2' position of the ribose ring of RNA. By contrast, the "D" in DNA stands for deoxy (lack of oxygen) in this position.
The mRNA in COVID-19 vaccines is so fragile that it must be packaged inside lipid nanoparticles. These lipid particles protect the mRNA, allowing it to reach and enter cells, where it lasts long enough to produce viral spike proteins that stimulate the immune system to recognize and fight the virus. The rapid mutation of the virus’s spike protein—something not fully anticipated when the first vaccines were developed—has reduced vaccine effectiveness over time. As a result, updated vaccines targeting newer variants are now provided periodically.
- Persistence of viral mRNA
Through natural selection, viruses have evolved several mechanisms to protect their mRNA, making viral replication more efficient. For example, they produce structures like 5' caps and 3' poly-A tails, which shield viral mRNA from the host cell’s natural mRNA degradation processes. While persistence varies based on several factors, vaccine mRNA typically lasts only hours, whereas viral mRNA can persist for days. Additionally, viral mRNA is continually replenished by the virus throughout the course of infection, further aiding its stability and replication.
- Comparison of the amount of vaccine mRNA and viral mRNA
This isn't even close. Vaccines provide a minuscule, non-replicating quantity of mRNA in a single dose. By contrast, viruses continually produce millions or even billions of copies during the infection, which are spread throughout the body. This vastly surpasses vaccines in both the quantity and distribution of mRNA. This is like comparing a rain puddle to the Pacific Ocean.
- Can the vaccines cause COVID?
No, this is impossible. Unlike the virus, which produces billions of copies during infection, the vaccine triggers the production of small, non-infectious fragments of the virus. These fragments are sufficient to evoke an immune response to the virus but cannot be infectious since they contain only very small parts of the virus that lack virtually all of the viral components required for replication.
- What about myocarditis?
There are known cases of myocarditis, an inflammation of the myocardium, the muscular layer of the heart wall, from the vaccine. However, a paper in the European Journal of Cardiology estimates that the incidence of the condition is approximately 100 times greater from infection than from the vaccine. A JAMA Internal Medicine study of more than 2 million vaccine recipients concluded: "No relationship between COVID-19 mRNA vaccination and postvaccination myocarditis can be established given the observational nature of this study." This is not to say that the issue of myocarditis should be dismissed outright.
ACSH friend Dr. Paul Offit, Professor of Pediatrics at the Children's Hospital of Philadelphia, and a world-renowned expert in vaccine research and development kindly took the time to clarify his position on the risks and benefits of the Covid-19 mRNA vaccines.
Everyone who is 6 months of age or older and has not been infected or previously vaccinated should get the vaccine to prevent serious illness and hospitalization. With healthy young people, the story is a bit different. The incidence of myocarditis in boys and men aged 16-29 is 1 in 6,600 after a second dose. Since otherwise healthy males in this group are very unlikely to become seriously ill they do not need an annual shot because the benefit does not clearly outweigh the risk. It's a case of low risk, low reward.
Dr. Paul Offit, private communication. November 6, 2024
Bottom line
The fears of mRNA vaccines are unwarranted. We are continuously exposed to foreign mRNA from viral and bacterial infection – to say nothing of the mRNA that is in the produce and meats we consume routinely. Following the infection, the body clears the foreign mRNA. Furthermore, the rapid degradation of vaccine mRNA ensures that it does not persist for long. And even if it did, the quantity of foreign mRNA in the vaccine is absolutely dwarfed by that produced by the virus. Nor can the vaccine mRNA alter our genome. The absence of the integrase enzyme makes this impossible. The vaccine cannot cause a COVID-19 infection since it produces non-replicating fragments of the viral spike protein but none of the viral machinery required for replication.
In short, all these fears of the COVID-19 vaccines are unfounded.
Josh Bloom
Director of Chemical and Pharmaceutical Science
Dr. Josh Bloom, the Director of Chemical and Pharmaceutical Science, comes from the world of drug discovery, where he did research for more than 20 years. He holds a Ph.D. in chemistry.
