Editorial: SARS-CoV-2 Vaccine Responses and Breakthrough COVID-19

In 2021, data from global disease monitoring and infection surveillance programs have shown that vaccination programs have reduced the incidence of SARS-CoV-2 infection and hospitalization and mortality rates. Currently, the US Centers for Disease Control and Prevention (CDC) identifies a fully vaccinated individual as being ≥14 days after the completion of all the recommended doses of a COVID-19 vaccine that has been authorized by the US Food and Drug Administration (FDA). A partially vaccinated individual is <14 days following primary vaccination or has not completed the vaccination program. Clinical studies and data on the vaccine status of populations have identified breakthrough COVID-19 cases in fully vaccinated individuals at 14 or more days after completing the recommended dose of an authorized SARS-CoV-2 vaccine. This Editorial presents an update on what has been learned in the past year on SARS-CoV-2 vaccine responses and breakthrough COVID-19.