Safety and efficacy of BCG re-vaccination in relation to COVID-19 morbidity in healthcare workers: A double-blind, randomised, controlled, phase 3 trial

Multiple BCG vaccinations for the prevention of COVID-19 and other infectious diseases in type 1 diabetes

“…Prior clinical trial data suggest that BCG vaccination exhibits ''off-target'' effects, i.e., viral and bacterial infectious disease prevention (and, in this study, prevention of SARS-CoV-2 viral infections) beyond its intended use in tuberculosis protection. [22][23][24][25]27,[37][38][39]50 Using the time period of the current COVID-19 trial, we analyzed infectious disease symptoms including COVID-19 and other infections. The cumulative infectious diseases reported by the subjects and represented as cumulative infections per patient were significantly fewer in the BCG versus placebo group (Poisson model comparing adverse events rates p = 0.004; Figures 4A and S3B).…”

“…With the onset of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, some epidemiology studies began to uncover an association between neonatal BCG vaccination and reduced morbidity and mortality from COVID-19, even in older adults decades after the typical neonatal vaccinations, on a country-by-country basis. [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] In some other global populations with varying neonatal exposures, different BCG strains, and other populations, benefits were not observed. 24,[41][42][43][44][45][46][47] Because the United States has never vaccinated newborns or adults with BCG, a randomized trial of BCG for possible protection from SARS-CoV-2 infection offers a clean comparison in a vaccinenaive adult United States population.…”

Long COVID and its Management

“…One study showed that BCG vaccine against COVID-19 was significant in young population, but was not as effective in older population [105]. However, another study from South Africa reported no protective effect by BCG vaccination against COVID-19 infection, severity and related mortality [106]. Above contradictory reports may contain analytic complications such as confounding mortality with tuberculosis and differences in demographics and diagnosis, so more human and animal studies are necessary to reveal whether influenza and BCG vaccines could stimulate the basal immune defense against SARS-CoV-2 [107,108].…”

Beneficial non-specific effects of live vaccines against COVID-19 and other unrelated infections

“…Ongoing RCTs are testing whether live attenuated vaccines reduce the incidence of COVID-19. 62 , 63 , 64 However, the non-specific effects of live attenuated vaccines might have little effect on the risk of infection but change the severity of infection. For example, RCTs of BCG administered to newborn babies found little effect on hospital admissions for sepsis, but the case fatality was reduced by 42% (95% CI 6–65%).…”