The efficacy of SARS-CoV-2 booster dose on SARS-CoV-2 inpatient epidemiology : an overview on disease severity and mortality

Abstract

BACKGROUND: The world is moving into the 3rd year of the SARS-CoV-2 pandemic. There is no doubt that vaccination has been crucial in significantly reducing the impact of the pandemic. Given the novelty of the SARS-CoV-2 vaccines and the waning immunity over time, data is required to determine the efficacy of SARS-CoV-2 booster doses.

METHODS: The comparative observational study included 451 eligible inpatients at Mater Dei Hospital, Malta. Hospital software and bed management databases were used to extract cases of confirmed infection in patients aged 17 years and older. Patients were stratified into two study arms: boosted and non-boosted cohorts. Disease severity was calculated based on clinical criteria and the Modified Chest X-Ray Score. A Pearson-Chi square test of independence was then used to analyse the data to acquire and compare rates of disease severity and mortality between the two groups.

RESULTS: 5.6% of non-boosted patients required intensive care unit admission compared to 0% of the boosted population. 8.8% of non-boosted patients developed severe illness compared to 5.5% of the boosted group. The study also found higher rates of ARDS and mortality in non-boosted inpatients, with a higher male predominance.

CONCLUSION: This study underpins the superior protection offered by a booster dose of SARS-CoV-2. It also points to a time-dependent waning in immunity, highlighting the importance of robust vaccination programmes.