BCG Vaccine’s Efficacy for COVID-19 & Respiratory Infections in Older Adults

The following is a summary of “Bacillus Calmette-Guérin vaccine for prevention of COVID-19 and other respiratory tract infections in older adults with comorbidities: a randomized controlled trial,” published in the June 2023 issue of the Clinical Microbiology and Infection by Koekenbier et al.

This study aims to determine whether Bacillus Calmette-Guérin (BCG) vaccination reduces the incidence of COVID-19 and other respiratory tract infections (RTIs) in elderly adults with at least one comorbidity. About 60-year-old or older community-dwelling adults with one or more underlying comorbidities and no contraindications to BCG vaccination were randomized 1:1 to BCG or placebo and monitored for six months. The primary outcome measure was a self-reported, test-confirmed incidence of COVID-19. 

Secondary endpoints included COVID-19 hospital admissions and clinically relevant RTIs (RTIs necessitating medical intervention, including but not limited to COVID-19). COVID-19 and clinically significant RTI cases were evaluated. Comparing incidences using Fine-Gray regression for accounting for contending events. A total of 6,112 participants with a median age of 69 (interquartile range: 65–74) and a median number of 2 (interquartile range: 1–3) comorbidities were randomly assigned to receive either BCG (n = 3,058) or placebo (n = 3,054) vaccination. About 129 BCG recipients reported COVID-19 infections compared to 115 placebo recipients [hazard ratio (HR), 1.12; 95% CI, 0.75–1.44]. Of 18 BCG and 21 placebo recipients were hospitalized due to COVID-19 (HR, 0.86; 95% CI, 0.40–1.64). 

During the study period, 13 BCG recipients died compared to 18 placebo recipients (HR, 0.71; 95% CI, 0.35–1.43). About 11 fatalities (35%) were attributable to COVID-19: 6 in the placebo group and 5 in the BCG group. Of 66 BCG and 72 placebo recipients reported clinically significant RTI (HR, 0.92; 95% CI, 0.66–1.28). BCG vaccination does not protect against COVID-19, COVID-19 hospitalization or clinically significant RTIs in elderly adults with comorbidities.

Source: sciencedirect.com/science/article/pii/S1198743X23000447