The inflammatory effects that a vaccine has on the body, shortly after injection, and the physical manifestation of that inflammation, is called it’s reactogenicity.
A vaccine that makes a larger proportion of recipients feel acutely under the weather (for no more than 24-48 hours), or more intensely under the weather than another, is more reactogenic.
This activation of the humoral arm of the immune system is what leads to the activation of the adaptive arm (antibody production and “remembered” immunity).
All this to say, the symptoms you may or may not feel 1-2 days after receiving a vaccine are not causing your body harm and are indicative of your body building an immune response.
*A detailed post about adjuvants (mentioned in the diagram) to come later this week!
Posted on Instagram on January 4, 2021.