In adults with post–COVID-19 conditions, a synbiotic preparation, SIM01, alleviated some symptoms at 6 mo

Question: In adults with post–COVID-19 conditions (PCC), does a synbiotic preparation (SIM01) alleviate symptoms compared with placebo?
Design: Randomized placebo-controlled trial (RECOVERY).
Blinding: Treatment allocation concealed; blinded (patients, care providers, investigators, and adjudication committee for end points and adverse event causality).*
Setting: Prince of Wales Hospital, Hong Kong.
Patients: 463 patients aged ≥18 years (mean age, 49 y; 65% women; 100% Chinese ethnicity; median time after COVID-19 diagnosis, 4 mo; mean number of PCC symptoms, 9) who had a previous diagnosis of COVID-19 confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) or rapid antigen test, PCC symptoms based on U.S. Centers for Disease Control and Prevention criteria, and ≥1 of 14 symptoms included in the Post-Acute COVID-19 Syndrome-14 questionnaire for ≥4 weeks after infection. Key exclusions: immunocompromised condition, inability to receive oral fluids, or gastrointestinal surgery in the past 30 days.
Interventions: Oral SIM01, containing 10 billion colony-forming units of 3 bacterial strains (Bifidobacterium adolescentis, B bifidum, and B longum) and 3 prebiotic compounds (galacto-oligosaccharides, xylo-oligosaccharides, and resistant dextrin) (n = 232); or placebo, including 1 mg of vitamin C (n = 231), each taken twice/d for 6 months.
Funding: Health and Medical Research Fund of Hong Kong and Hui Hoy and Chow Sin Lan Charity Fund.
Bottom line: In adults with PCC, a synbiotic preparation (SIM01) vs. placebo alleviated some symptoms at 6 months.