Introduction: The COVID-19 pandemic resulted in movement and service restrictions during 2020 and 2021 that may have affected the essential immunization services in Sierra Leone. We analyzed the national routine immunization (RI) data to assess the effect of the COVID-19 pandemic in immunization coverage. Methods: Using national RI data for the period 2018 to 2021, we computed vaccination coverages for pentavalent vaccine (Penta1 and Penta3), first and second doses of measles-rubella (MR1 & MR2). We also computed the dropout rates (DOR) for the same antigens. A coverage of ≥90% and a DOR of