About 3 weeks ago, I received the first dose of the Pfizer COVID vaccine and I explained why I ultimately decided to get the vaccine when I was initially hesitant. Other than the fact that my non-dominant arm felt pretty sore for the first few days, I did not exhibit any other symptoms. So far, so good.
Today, I received the second dose. I took it early afternoon and as of the time of me posting this, it is evening. Thus far, I am not feeling any different than before I took the shot other than the arm soreness. In fact, my arm actually feels less sore than it did at the same point after my first dose. Whether I wake up the next morning feeling normal or very sick remains to be seen, but I seem to be off to a good start.
But why do some people feel sick after the second vaccine? The gist of it is that when you get the first dose, your immune system is in the process of learning about COVID's profile. It's a gradual process as your adaptive immune response is not going full throttle. This is why you tend to not feel much side effects. To recap the science behind it:
1. Our cells' ribosomes will bind to the mRNA from the vaccine and translate it into the virus' spike proteins.
2. The antigen-presenting cells will engulf the spike proteins and present pieces of them at the cell membrane via the MHC-2 complex.
3. The helper T-cells will bind to the MHC-2 proteins presenting the antigen.
4. The helper T-cells will proliferate into memory T-cells and effector T-cells. The latter releases cytokines, a chemical "alarm bell", to activate the B-cells.
5. The B-cells will divide into effector B-cells and memory B-cells. The former churns out antibodies for our immune systems to immediately fight the virus. The latter will allow our immune systems to react to the same infection more quickly if the virus invades our bodies again.
When you are re-exposed to the same spike proteins from the second dose, your immune system will react more quickly because it already has the memory B-cells to recognize the proteins. Your body may also heat up into a fever to further enhance the immune response. This is due to the rapid release of cytokines, which stimulates the hypothalamus in your brain to produce prostaglandins. This biomolecule will signal your body to heat up into a fever.
At the end of the day, though, it is up to you to decide, not me. Maybe my explanation of the science behind the mRNA vaccine and the reasons for the side effects has made you feel more comfortable with at least the Pfizer or Moderna vaccines. Maybe you think this is all bullcrap and I won't blame you. But at the very least, conduct your own research on each vaccine's mechanisms, their side effects, and efficacy rates before deciding.
Fingers crossed that my second shot won't knock me out.
