Effectiveness of Coronavirus Disease 2019 Vaccines in Preventing Infection, Hospital Admission, and Death: A Historical Cohort Study Using Iranian Registration Data During Vaccination Program.

Background: There are some concerns about the effectiveness of the inactivated and vector-based vaccines against severe acute respiratory syndrome coronavirus 2 in real-world settings with the emergence of new mutations, especially variants of concern. Data derived from administrative repositories during mass vaccination campaigns or programs are of interest to study vaccine effectiveness.

Methods: Using 4-repository administrative data linkage, we conducted a historical cohort study on a target population of 1 882 148 inhabitants aged at least 18 years residing in southern Iran.