The persistent and often debilitating symptoms of long Covid have perplexed researchers and healthcare professionals alike, prompting a myriad of investigations into potential treatments and management strategies. In a significant development, a recent study involving over 450 participants has unveiled promising results, suggesting that a daily combination of prebiotics and probiotics could be a key to alleviating some of the lingering effects of long Covid.




Long Covid, formally known as post-acute sequelae of SARS-CoV-2 infection (PASC), is a condition characterized by persistent symptoms that endure for months or even years after the initial Covid-19 infection. Fatigue, memory loss, difficulty concentrating, and gastrointestinal issues are among the diverse range of symptoms reported by individuals grappling with long Covid. This study, conducted by a team led by Siew Ng at the Chinese University of Hong Kong, introduces a novel approach to addressing these lingering symptoms through the modulation of gut health.


The rationale behind this approach is rooted in previous research indicating that individuals with long Covid exhibit lower levels of specific gut microbes compared to those without the condition. Notably, the deficit is observed in gut bacteria responsible for producing short-chain fatty acids, compounds that play a crucial role in regulating immune responses. Recognizing this association, the researchers aimed to enhance short-chain fatty acid production by formulating a concoction named SIM01.


SIM01 comprised a combination of three probiotics – live strains of beneficial bacteria – and three prebiotics, compounds that nourish and support the growth of beneficial gut microbes. The study involved 232 adults who were administered the SIM01 cocktail, while a control group of 231 adults received a mixture containing starch and low-dose vitamin C. Both mixtures were consumed twice daily over a span of six months.


The participants, all of whom had previously tested positive for Covid-19 and met the criteria for long Covid outlined by the US Centers for Disease Control and Prevention, were assessed for 14 long Covid symptoms before and after the six-month treatment period. The results revealed a notable improvement in five key symptoms – fatigue, memory loss, difficulty concentrating, general unwellness, and gastrointestinal upset – among those who received SIM01. On average, these individuals were approximately 2 to 2.5 times more likely to experience relief from these specific symptoms.


Crucially, the study found no significant side effects associated with the administration of SIM01. Additionally, an analysis of fecal samples collected from participants before and after the trial demonstrated that SIM01 had a positive impact on the diversity of gut microbes, fostering the growth of beneficial bacteria.


Siew Ng, the lead researcher, emphasized that the observed changes in the gut microbiome could extend beyond addressing long Covid symptoms. The enhanced diversity and growth of beneficial gut bacteria resulting from SIM01 treatment suggest its potential applicability in treating other conditions linked to disrupted gut microbiomes, such as chronic fatigue syndrome.


However, the mechanisms through which these alterations in the gut microbiome translate into alleviation of long Covid symptoms remain somewhat enigmatic. Timothy Sampson, an expert from Emory University in Georgia, pointed out that while the microbiome has the capacity to influence immune responses, it is not conclusively established whether the immune system is the sole driver of long Covid symptoms.


The study's findings open new avenues for research and offer a glimmer of hope for individuals grappling with the lingering effects of long Covid. The intersection of gut health and persistent viral symptoms introduces a novel dimension to our understanding of post-Covid conditions, potentially paving the way for innovative therapeutic interventions. As researchers delve deeper into the intricate connections between the gut, the immune system, and long Covid, the prospect of targeted and effective treatments continues to evolve. The quest for solutions to the complex puzzle of long Covid takes an encouraging step forward with the promising outcomes of this probiotics and prebiotics study.