Assessing the Dynamics of COVID-19 Morbidity and Mortality in Response to Mass Vaccination: A Comparative Study Between Saudi Arabia and the United Kingdom

Background Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, efforts have been in place to tackle the infection. Mass vaccination programs were regarded as the sole solution to end the pandemic. Here, we compare the differential impact of mass vaccination programs in Saudi Arabia (SA) and the United Kingdom (UK) on COVID-19 morbidity and mortality to determine whether vaccines were solely responsible for the changes observed in the disease dynamics. Methodology We retrospectively collected the number of new cases and deaths throughout 2021 in both SA and the UK. Similarly, the number of vaccine doses delivered in both countries was collected and compared. Results Through 2021, the percentage of daily COVID-19 cases was significantly less in SA than in the UK; however, the percentage of deaths was higher in SA. Interestingly, the percentage of daily cases was significantly reduced in SA upon vaccination. The vaccination coverage of both the first and second doses was higher in the UK compared to SA, and, consequently, the percentage of deaths was significantly reduced in the UK compared to SA. Conclusions The UK vaccination program succeeded in curbing the number of daily deaths compared to SA. SA had better control over the percentage of daily cases, primarily due to the restrictive measures and vaccination, such as the imposed social distancing and mandatory face masks.