17-07-2025
Long Covid: Probiotics could form a potential treatment
There is no single treatment option for those with post-acute Covid-19 syndrome or long Covid, which remains a serious, but poorly-addressed public health concern worldwide.
Globally, it is estimated to have affected some 400 million individuals who experience lingering symptoms such as brain fog, digestive issues and general malaise.
In an attempt to find a solution, a team of researchers from the Chinese University of Hong Kong (CUHK) decided to assess a symbiotic preparation (a formulation that combines probiotics and prebiotics) to see if it could alleviate long Covid symptoms.
This is as previous CUHK studies had shown that long Covid patients had altered gut microbiomes.
Their formulation was developed based on a decade of research on Asian gut microbiomes.
It consists of three probiotics ( Bifidobacterium adolescentis , Bifidobacterium longum and Bifidobacterium bifidum ) and three prebiotic fibres (galactooligosaccharides, xylooligosaccharides and resistant dextrin).
From 2021 to 2022, 463 recovered patients with at least one long Covid symptom were recruited for the randomised controlled trial in Hong Kong.
Nearly 70% were suspected to have been infected with the SARS-CoV-2 Omicron variant.
The patients were randomly assigned to receive either the formulation or a placebo containing low dose Vitamin C for six months.
At the end of the study, 70% of the former reported improvement in digestive problems, compared to 54.1% in the placebo group.
The group taking the formulation also had more improvements for symptoms like fatigue, difficulty in concentration, memory loss and general unwellness, compared to those taking the placebo.
Analysis of their stool also showed that the formulation resulted in increased bacteria diversity, increased abundance of 'favourable' bacteria, and reduced abundance of 'unfavourable' bacteria in the gut.
'To our knowledge, this is the first clinical trial to show that modulation of the gut microbiome can improve long Covid symptoms, including memory and concentration problems.
'These data support the importance of the gut-brain axis.
'Restoring a healthy gut microbiota is a novel approach to improve neurological symptoms via the production of beneficial metabolites from gut bacteria that circulate to the brain to improve brain function,' says study lead investigator and gastroenterologist Professor Dr Siew C. Ng.
The groundbreaking research was published in the March 2024 issue of the Lancet Infectious Diseases journal.
'We've seen that gut bacteria colonisation takes about six to 12 months to happen, so I tell my patients to take the formulation for a minimum of six months.
'If symptoms improve, they can come off it.
'A small proportion of them can do this, but over time, the bacteria may drop depending on diet, whether you received antibiotics, etc.
'However, a lot of patients are still on it after three years as they reported that once they stopped taking it, some of their symptoms returned.
'There is really no one-size-fits-all approach,' she says in a recent interview.
Probiotic supplements are generally taken for health benefits, but if you're already healthy, do you need them?
Prof Ng says: 'It's all right to be sceptical of probiotics as there are so many out there that claim to work.
'You're taking them for prevention, but it makes no difference if you're healthy as you won't know if it is working!'
The associate dean of CUHK's Faculty of Medicine, who has been doing probiotics research for decades, is on a mission to educate doctors and pharmacists on how to choose or prescribe probiotics.
'Personally, I need scientific back-up to gauge the effectiveness of probiotics.
'We have isolated strains in our laboratory and know that not all of them have equal benefits.
'We've done clinical studies that showed no difference in gut microbiota when you take some of them.
'My advice to the public is to first try lifestyle measures to modulate the gut before taking probiotics.
'Then look at the large clinical studies and digest the information before deciding if you really need these supplements,' she says, adding that their formulation is now available in selected pharmacies in Malaysia.
Click here for more on CUHK's research on restoring the gut microbiota to address eczema in children.
