Question: There have been many posts online regarding the vaccines that say the vaccines will change a person’s DNA. That stem cells have been used to develop the vaccines. What should we be concerned about regarding the vaccines, the repercussions?
Answer: There’s a LOT of misinformation about vaccines, especially the new mRNA vaccines, like those developed by Pfizer and Moderna. Rest assured, mRNA vaccines do NOT interact with a person’s DNA and are totally UNABLE to affect or change a person’s DNA. We have nothing to worry about on that front. That said, there are real side effects that have been reported with both vaccines, but they have generally been short-lived and none have been serious. Read on to learn more about how mRNA vaccines work and about expected side effects. For the sake of time today, I’m going to punt on your question on stem cells, but if you want to read more check out this article from STATNews and this one from Science.
How do mRNA vaccines work? This is where a lot of us wish we remember more from our biology classes! Here’s a quick synthesis: DNA is our genetic codebook, located in each cell’s nucleus (deep inner core), which is protected by the nuclear membrane. Ribosomes are located outside the nuclear membrane in the cytoplasm. Ribosomes have the job of making proteins (proteins are the “workhorses” of the cell, doing a whole range of things). But ribosomes can only make proteins based on instructions they receive from messenger RNA (mRNA). Once mRNA shares its instructions, it quickly degrades. Tying this all back to an mRNA vaccine: the shot is administered and it delivers to the local cells mRNA carrying instructions on how to build a piece of the “spike protein” that is unique to SARS-CoV-2. The ribosomes use these instructions to make the spike protein protein piece, which then leaves the cell. As soon as the spike protein piece leaves the cell, the body’s immune system kicks in. Recognizing a protein that does not belong, the immune system produces antibodies and sends T-cells to fight off what it thinks is an infection. This response then allows the body to develop defenses specifically against SARS-CoV-2, making the immune system primed to protect against future infection. An analogy commonly applied is that of a cookbook– DNA is our treasured genetic cookbook that is stored in the library and never removed. If we want to use a recipe from the cookbook, a scribe writes it down on a recipe card (mRNA) that we’re allowed to take to our kitchen (ribosomes) to make the recipe (proteins). After we make the recipe, the card is tossed into the trash where it quickly degrades. The DNA cookbook remains unchanged. To learn more, check out CDC’s Understanding and Explaining mRNA COVID-19 Vaccines. This Q&A on vaccines from Emily Oster is also super informative.
What about side effects? We don’t have much information to go on here as we’re still working from press releases and related news reports. The FDA will provide a more thorough review of the data in preparation for its emergency use authorization determination, and we should also expect to see peer reviewed studies soon. In the meantime, what we do know is that fatigue and pain are both relatively common reactions to the Moderna and Pfizer vaccines (Table 1). Science had an informative article on this topic a couple of weeks back, Fever, aches from Pfizer, Moderna jabs aren’t dangerous but may be intense for some.
Table 1. Side effects reported among at least 2% of trial participants at dose 1 and/or dose 2, Moderna and Pfizer (from Moderna press release, Pfizer press release)
