The US Centers for Disease Control and Prevention (CDC) explain mRNA vaccines contain material from the virus that causes Covid-19, and the material “gives our cells instructions for how to make a harmless protein unique to the virus”.
The CDC added: “After our cells make copies of the protein, they destroy the genetic material from the vaccine.
“Our bodies recognize that the protein should not be there and build T-lymphocytes and B-lymphocytes that will remember how to fight the virus that causes Covid-19 if we are infected in the future.”
Compared to other forms of vaccine, mRNA vaccines can be made very quickly.