This study looks at how safe and effective the mRNA COVID-19 vaccines are for young children. It is for healthy children aged 6 months to less than 6 years. The study checks vaccines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. There are four different parts:

Key Points:

• The study has several parts, and each part involves different doses and schedules. Some children will get two doses, and some will just get one.
• The study is for children who have and haven't had any COVID-19 vaccines before. It's important that their health conditions are stable.
• Children with recent COVID-19 infection, allergies to vaccine parts, or certain health conditions can't join.

Parents must agree to the study and follow all the steps. The study aims to find out if these vaccines are safe and help protect children from COVID-19. Children will have to visit the study site multiple times, and they will be checked for any side effects from the vaccine. Parents should ensure their child meets all the participation rules before considering joining the study.