COVID-19 vaccines are safe and effective. The first COVID-19 vaccines authorized in the United States were developed using Messenger RNA—also called mRNA. The mRNA technology is new, but not unknown. They have been studied for more than a decade. mRNA vaccines do not contain a live virus and do not carry a risk of causing disease in the vaccinated person.
Millions of people in the United States have received COVID-19 vaccines and these vaccines have undergone the most intensive monitoring in U.S. history.