How vaccines work against COVID-19: Science, Simplified
fter we have been exposed to an infection, our immune system remembers the threat, in particular by producing antibodies. These are proteins that circulate in the blood and throughout the body; they quickly recognize and disable the invader upon contact, thereby preventing or minimizing illness. This is why we usually do not get sick with the same bug twice; we are immune. Vaccines mimic this process, encouraging the immune system to make antibodies without us having to go through the illness.