Are mRNA vaccines uncontrollable?

In a widely circulated video, National Institutes of Health director Dr. Jay Bhattacharya claims that COVID vaccine use has dropped because mRNA vaccines are unsafe and unreliable, since scientists can’t fully control how much antigen is made, where it goes in the body, or whether the right proteins are produced.

mRNA vaccines, like the ones made for COVID-19, work by giving the body a tiny set of instructions. These instructions tell your cells to make a harmless piece of the virus, usually the spike protein. This protein cannot cause COVID-19, but it teaches your immune system what the real virus looks like. Once your body recognizes it, your immune system learns to fight it off if you ever come into contact with the real virus. After the protein is made, your body quickly gets rid of the mRNA instructions, usually within a few days. Scientists have studied this process very carefully, and they have shown that it works the way it is supposed to without causing the body to lose control or make dangerous mistakes.

The claim that scientists cannot control the amount of antigen (the spike protein) made by your cells is misleading. The amount of mRNA given in each vaccine dose is very carefully measured. Clinical trials and studies after the vaccines were released have shown that the immune response is consistent across millions of people. While it is true that different people’s bodies can react slightly differently (like some people having a sore arm and others not), that is normal for all vaccines and even for regular infections. There is no evidence that the mRNA vaccines cause dangerously large or uncontrolled production of spike protein.

The idea that the spike protein could go “anywhere” in the body in dangerous ways is also not supported by science. Studies have shown that most of the mRNA stays near the injection site, usually the muscle in your upper arm, and nearby lymph nodes. These are exactly the places where your immune system needs to be activated. The body is very good at breaking down the mRNA quickly, and your immune system destroys the spike protein itself after it does its job of teaching. There is no evidence from millions of vaccine doses that the spike protein travels around the body, causing harm.

Another false claim is that the body often makes the wrong proteins from the mRNA vaccines. Scientists designed the mRNA very carefully so that it would be copied correctly. There is some natural variation anytime your body makes proteins, but this is very small and not harmful. If serious errors happened often, we would have seen major problems in the tens of millions of people who got vaccinated. Instead, what we saw was that vaccinated people were much less likely to get very sick, go to the hospital, or die from COVID-19.

Finally, the scientists who developed the mRNA technology indeed won a Nobel Prize, but that doesn’t mean the technology is unfinished or unsafe. It means their discovery was important and helped save millions of lives. Scientists will keep improving vaccines in the future, just like they always have with every kind of medicine. However, the COVID-19 mRNA vaccines are already very effective and safe, as shown by many studies around the world.

Sources:

• https://www.cdc.gov/coronavirus/2019-ncov/vaccines/facts.html
• https://www.nature.com/articles/s41541-021-00398-6
• https://www.nejm.org/doi/full/10.1056/NEJMoa2035389
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7929134/
• https://www.who.int/news-room/questions-and-answers/item/coronavirus-disease-(covid-19)-vaccines-safety
• https://www.fda.gov/media/144245/download
• https://www.science.org/doi/10.1126/science.abn7591