How COVID-19 Vaccine Works

The COVID-19 vaccine development is a very clever vaccine development. It is neither a live-attenuated virus (Sabin polio vaccine) nor a dead virus vaccine (Salk polio vaccine, the annual flu vaccine). The sequence of the coronavirus virus was mapped out and that part of the sequence that codes for the “corona” of the coronavirus, its protein spike, its surface signature, which we call an antigen, is used to assemble messenger RNA. That messenger RNA is then injected into a person—with Moderna and Pfizer it is in a carrier, with J&J it is attached to a harmless virus—that once injected is taken-up by certain dendritic lymphocyte white blood cells. Once inside the cell, the injected messenger RNA finds its way to the cytoplasm machinery that codes for proteins and sort of hijacks it. There the vaccine messenger RNA codes for the protein spike, the antigen of the coronavirus capsid. Those proteins spikes then leave the cell where, as they’re roaming in the blood circulation, “other” lymphocyte white blood cells recognize the foreign protein spike and launch an immune reaction. That immune reaction is the production of antibodies and lymphocytes, both of which have memory.

This is not a shield like “raise the shields” from Star Trek. Once successfully immunized with COVID-19 vaccine, the virus can still enter a person. It is just that it fails to launch an infection, it fails to enter certain cells it would like to target. Why? Because the immune system is primed, it has the antibodies with memory and lymphocytes with memory that attack the virus like a rabid dog. It is unclear the correct word to describe a vaccinated person with the virus (or bacteria) within their system but unable to launch an infection.