The covid vaccine is an mRNA vaccine which uses mRNA created in a lab. This mRNA teaches our cells how to create a harmless piece of protein to trigger an immune response.
There are three covid vaccines available in the US for adults aged 18 years or older. They are Moderna, Pfizer-BioNTech, and Johnson and Johnson's Janssen vaccines. Children aged 5 years or older are eligible to recieve the Pfizer-BioNTech vaccine.
Children from ages 5-11 are only eligible for the 2 dose Pfizer-BioNTech
Learn more about the vaccines: