If you’re worried about long-term vaccine effects, let’s talk about how quickly the components disappear from your system. I find this to be a very important but poorly understood aspect of vaccination. Vaccines introduce your body to the pathogen (or a piece/mimic of the pathogen) and then exit the picture. Your immune system takes over and creates the lasting memory for long-term protection.
1. mRNA is a highly fragile form of nucleic acid that typically lasts only hours in cells and even less time in the blood. It is for this reason that it is delivered in a lipid nanoparticle – to stabilize it. The mRNA is used in the cytoplasm to create protein and then degrades within hours.
2. Protein is broken down within cells by proteosomes or taken up and destroyed by immune cells. The half-life of proteins is typically on the order of days. The spike protein half-life is no exception.
3. Lipid nanoparticles are also metabolized quickly in the body and excreted. The rate of metabolism depends on the exact lipids but certain chemical characteristics will decrease the half-life. Several lipids in the current mRNA-based vaccines have some of these characteristics that make them more biodegradable.
So that’s it! Because of the transient nature of the components, long term effects are very low concern.