Gut Bacteria Cocktail Helps Long COVID

— Oral treatment alleviates symptoms better than placebo

Last Updated May 18, 2023
MedpageToday

CHICAGO -- A daily capsule containing live intestinal bacteria appeared effective for relieving symptoms of post-acute COVID-19 symptoms, better known as "long COVID," a researcher said here.

In a randomized, placebo-controlled trial, patients receiving the active microbiome treatment called SIM01 for 6 months were more likely than controls to see improvements in digestive problems, fatigue, difficulty with concentration, memory impairment, and "general unwellness," said Raphaela Iris Lau, MSc, a doctoral student at Chinese University of Hong Kong.

For example, 70.2% of patients with digestive complaints at enrollment said they felt better after 6 months with SIM01, compared with 54.1% of those on placebo, Lau told attendees at a late-breaking abstract session at the annual Digestive Disease Week conference.

Findings were similar for the other four symptom categories, with improvement rates of 42.0%-77.3% with the microbiome product. Response rates with placebo were roughly 15-25 points lower in all categories, with P values well below 0.05.

SIM01 comprises three Bifidobacteria species along with three types of probiotic substances to help support their growth, with a total of 20 million colony-forming units per daily dose. An open-label pilot study that began in late 2020 and reported last year found that the product reduced pro-inflammatory cytokine release and promoted anti-SARS-CoV-2 antibody development.

Dysbiosis is among the characteristics of long COVID, Lau said, suggesting that a restorative microbiome therapy might help patients recover faster.

For the current study, Lau and colleagues enrolled 463 patients in the Hong Kong region who had confirmed COVID-19 at least 4 weeks previously and who had at least one of 13 long COVID symptoms. Symptoms were assessed with a 14-item questionnaire (administered by a professional); an additional eight-item, self-administered questionnaire covered gastrointestinal symptoms specifically. Patients were randomized 1:1 to SIM01 or placebo (matching vitamin C capsule).

Mean patient age was about 50, and 65% were women. Acute COVID-19 had been asymptomatic or mild in some 85% of participants.

Lau explained that her group expected at the outset that SIM01 would relieve symptoms in approximately 70% of patients, with a placebo response rate of 50%, which guided the trial's enrollment target. Improvements over placebo had to meet a P threshold of 0.0036 after Bonferroni correction for the large number of symptom types tracked.

Thus, while SIM01 was numerically superior to placebo for all 13 symptom categories, only the five noted earlier were significant to that degree.

Within the overall gastrointestinal symptom category, Lau reported that, after Bonferroni correction, SIM01 was better than placebo at relieving diarrhea, constipation, abdominal pain, bloating, vomiting, and epigastric pain.

Adherence in the trial was excellent, with more than 80% of both arms taking more than 90% of their daily doses. Five patients in the SIM01 group had serious adverse events versus one in the placebo group, but Lau said none were considered treatment-related. Adverse events overall were infrequent, affecting only about 10% of participants in each group.

Limitations to the study included lack of data on the degree of symptom relief and the sample's overwhelming Chinese ethnicity. About 70% of patients had been infected with the Omicron SARS-CoV-2 variant and the rest with earlier strains, meaning that these results might not apply fully to patients infected with newly emerging variants.

Correction: Lau's degree has been updated.

  • author['full_name']

    John Gever was Managing Editor from 2014 to 2021; he is now a regular contributor.

Disclosures

Funding for the study was not reported.

Lau declared she had no relevant financial interests.

Primary Source

Digestive Disease Week

Source Reference: Lau RI, et al "Modulation of gut microbiome alleviates post-acute COVID-19 syndrome: A randomised, triple-blind, placebo-controlled trial (RECOVERY study)" DDW 2023; Abstract 913a.