Probiotics may thwart symptoms of Covid-19

“Recent studies suggest that prophylaxis with Lacticaseibacillus​ species specifically can prevent the development of upper and lower RTIs in healthy subjects…Thus, modulation of the gut microbiome via probiotics is a promising strategy for prophylaxis and mitigation of Covid-19,” the researchers wrote. 

The Lacticaseibacillus rhamnosus​ GG (LGG) is particularly encouraging given the success of Lacticaseibacillus​ strains in numerous in vivo​ studies and clinical trials in healthy subjects, they added.

As Covid-19 continues to pose a global health challenge, research is showing a potentially significant role of the microbiome and dysbiosis in disease severity and development of long-Covid and “studies evaluating the role of probiotics and other methods of microbiome optimization are urgently needed,” the scientists noted. “Probiotics may be a low-risk, low-cost and easily implementable modality to reduce risk of Covid-19.”

However, the researchers reiterated that vaccination should remain the first line in the prevention of the disease. 

Study details​

To investigate the efficacy of the probiotic LGG as a post-exposure prophylaxis against Covid-19, 182 participants were enrolled in the study and took either LGG or placebo once daily for 28 days. The LGG capsules, made by Culturelle (DSM), contained ten billion colony forming units of the strain.

Additionally, participants needed to be exposed to a household contact diagnosed with Covid-19.

Enrollment began on June 24, 2020 and was stopped early on June 2, 2021, when most individuals approached for the study reported already been vaccinated and were therefore ineligible.

Those randomized to LGG had fewer symptoms compared to those receiving placebo.

“Our study suggests that LGG is well-tolerated and is associated with prolonged time to development of Covid-19 infection, reduced symptomatic disease and changes to gut microbiome structure,” the researchers wrote.

Symptoms tracked among participants included fever/chills, headache, muscle aches, runny nose, sore throat, cough, shortness of breath, nausea or vomiting, diarrhea, stomach upset or pain, excessive bloating or gas, constipation, loss of sense of smell, loss of sense of taste, rash, painful toes or other symptoms as reported. Secondary factors monitored included time to Covid-19 diagnosis, incidence of Covid-19 diagnosis, severity of symptoms and duration of symptoms.

A total of 260 stool samples were received from 106 participants. Participants who received LGG had a significantly greater abundance of L. rhamnosus​ compared to participants who received placebo.

“Microbiome analyses confirmed that L. rhamnosus​ abundance was significantly increased in participants who received LGG compared to placebo, suggesting that participants were adherent with study therapy and that microbial community structure differentiated in response to probiotic treatment,” the researchers wrote.

Limitations​

The study had several constraints.

“First, we were limited in total sample size and time of study enrollment due to difficulty with recruitment during concurrent vaccine rollout, which increasingly limited the eligible population,” the scientists noted.

Additionally, LGG and other probiotics may cause gastrointestinal side effects, potentially influencing the measurement of symptoms, although fewer GI side effects were recognized in the probiotic group.

Finally, participants self-reported their symptoms rather than through a laboratory-confirmed infection. Covid-19 meant research was conducted remotely, including data collection and participants were not examined by physicians directly.

Source: Clinical Nutrition​
“Efficacy of probiotic treatment as post-exposure prophylaxis for COVID-19: A double-blind, Placebo-Controlled Randomized trial”
doi: doi.org/10.1016/j.clnu.2023.11.043​
Authors: Paul E. Wischmeyer et al.