Inclusion Criteria:  18 years of age or older, vaccinated with 1 dose of Sputnik V, AstraZeneca or Sinopharm vaccine up to 60 days prior to enrollment (according to the platform of the vaccine received as the first dose) or not vaccinated for the mRNA-1273 / mRNA-1273 Arm With and without identified risk factors for COVID-19 Signature of the informed consent Remain in the jurisdiction where your study began until the end of it Be able to understand and sign the informed consent  Exclusion Criteria:  Patients with immunocompromise due to underlying disease or immunosuppressive treatment Pregnant and breastfeeding people Being registered in the National Health Surveillance System for having suffered COVID-19 (symptomatic or asymptomatic) or having a positive IgG result in nucleocapsid ELISA in the sample taken on "DAY 0" for people who had received Sputnik-V or AstraZeneca as the first dose Having had a severe allergic reaction (anaphylaxis) to any vaccine