Probiotics for preventing or treating COVID-19; a systematic review of research evidence and meta-analyses of efficacy for preventing death, severe disease, or disease progression.

Probiotic consumption was associated with significantly longer hospital stays in two out of four studies that assessed this outcome, contrasting with probiotic therapy being associated with a significantly shorter hospital stay due to COVID-19 in one study, suggesting a possible trend consistent with probiotics worsening rather than shortening COVID-19 duration.

also in 590 other papers