Probiotics in the Fight Against COVID-19

Probiotics in the Fight Against COVID-19

A Canadian clinical trial (known as PROVID-19) is currently exploring the idea that probiotics can “reduce the duration and symptoms of COVID-19 in a symptomatic population tested positive to SARS-CoV-2, self-caring at home”.

It is certainly already well established that probiotics, among many other things, also serve to support the immune system, and to reduce the proliferation of pathogenic microorganisms. And, a good portion of the deaths actually due to COVID-19 are caused by secondary infections, most commonly pneumonia.

In May 2020, the medical journal Frontiers in Public Health published an opinion article titled, “Using Probiotics to Flatten the Curve of Coronavirus Disease COVID-2019 Pandemic”, in which they had this to say: “Evidence for antiviral activity of probiotic strains against common respiratory viruses, including influenza, rhinovirus, and respiratory syncytial virus comes from clinical and experimental studies. While none of these effects or mechanisms have been tested on the new SARS-CoV-2 virus, this should not negate considering this approach, especially when effects of probiotics against other coronavirus strains have been reported.

Furthermore, patients are dying from secondary bacterial infections. A recent study in mice has shown that oral administration of Lactobacillus acidophilus CMCC878, started 24 h after pulmonary inoculation of Pseudomonas aeruginosa and Staphylococcus aureus reduced bacterial load in the lungs, and decreased lung damage and systemic inflammation.” (Source)

Chinese Research

The PROVID-19 researchers (University of Sherbrooke, Quebec) were aware of this U.S. data, and had observed that Chinese doctors have been using probiotics, along with their other treatment protocols, since COVID-19 arrived on the scene. As well, prior to COVID, Chinese researchers discovered that specific probiotics treated “ventilator-associated pneumonia” (VAP) in patients undergoing mechanical ventilation, and helped speed their recovery.

In this study, 100 adult critically ill patients undergoing mechanical ventilation for >48 hours were randomly assigned to either the probiotic or the control group. The patients in the probiotic group received 2 capsules of probiotic preparation containing Lactobacillus, Bifidobacterium, and Streptococcus spp., and those in the control group received placebo daily for 14 days.”

The patients in the probiotic group had a lower incidence of statistically microbiologically confirmed VAP. The duration of intensive care unit (ICU) and hospital stay was also lower in the probiotic group. More than half of the patients in the control group had gastric residuals during ICU stay, compared with only 30% of patients in the probiotic group.” (Study)

Given this earlier Chinese research, it is no surprise that China’s National Health Commission was suggesting the use of probiotics to help treat COVID-19 when the virus first showed up (around Feb 2020). However, there was, obviously, at that time no data specific to COVID-19, so researchers from the Centre for Gut Microbiota Research, at the Chinese University of Hong Kong (CUHK), began to gather data, collecting stool samples from 15 patients with COVID-19.

After determining that “the composition of gut micro-organisms (microbiota) in COVID patients is very different from uninfected individuals”, with COVID patients lacking certain good bacteria known to regulate the immune system, the CUHK team expanded their data collection. They collected stool samples from 150 patients with COVID-19, and from 1,500 healthy people.

Based on this data, the researchers put together a formula of prebiotics and Bifidobacterium strains designed to address COVID-19 induced imbalances in gut bacteria. They then carried out a study with COVID patients and a control group. The CUHK pilot study found that a higher percentage of the COVID patients who received the probiotic fully recovered, and that the group receiving the probiotic formula developed more antibodies against COVID-19 than the control group.

Post-COVID Symptoms

This team is now conducting more studies to determine if their probiotic formula can help prevent residual symptoms of COVID-19, as it was noted that those who recovered from COVID-19 still had high levels of “abnormal” gut bacteria, accompanied by low levels of good bacteria, compared to healthy people. And, it is currently acknowledged that many survivors of this virus are left with painful symptoms that are slow to resolve.

Alterations of both bacterial and fungal microbiome in a subset of COVID-19 patients persisted even after clearance of SARS-CoV-2 virus from nasopharyngeal samples and resolution of respiratory symptoms. This underscores a potential prolonged detrimental effect of secondary infection on host health after SARS-CoV-2 infection cautioning on monitoring of patients with COVID-19 even after recovery.”

While coronavirus passes quickly for most, some people are suffering long-term effects including persistent symptoms of fatigue, dyspnoea and joint pains, that continued for weeks or months after initial onset of symptoms. In this regard, we posit that the dysbiotic gut microbiome could contribute to immune-related health problems post-COVID-19 and future long-term observational studies are needed to confirm this hypothesis.” (CUHK Study)

The Canadian study out of Quebec is also looking at the potential benefits of probiotics for treating “long-haul COVID-19”, extending patient monitoring for up to 55 days.

Cytokine Storms

As mentioned at the beginning of this newsletter (in the material from Frontiers in Public Health), probiotics also served to reduce systemic inflammation. Like vitamin D, probiotics may help prevent the inflammatory cytokine storms responsible for some of the worst symptoms of COVID. (See this newsletter for more on vitamin D and cytokine storms.)  Cytokines are small proteins released by immune cells, and are required by the body to respond to and kill viruses. However, the overproduction of cytokines leads to an inflammatory “storm”, which can damage many organs, including the eyes and the brain. Preventing cytokine storms from occurring will lessen the chances that a patient needs to be admitted to an Intensive Care Unit, and reduces the need for being put on a ventilator.

According to the CUHK study, “analysis of blood samples showed that the microbial imbalance found in the COVID patients was also associated with raised levels of inflammatory cytokines and blood markers of tissue damage”.

Which Probiotics?

Before the Quebec and CUHK studies were initiated, a clinical overview was published by Zhejiang University (Medical Sciences), titled “Management of COVID-19: the Zhejiang Experience”. This study found that patients with mild COVID-19 symptoms were more likely to have taken probiotics (along with standard medical antiviral treatment), than those manifesting worse symptoms. (Study)

However, the probiotics discussed in this overview were simply defined as Lactobacillus and Bifidobacterium, which only represent the general species of bacteria, not the specific type, nor the strain. The CUHK study was also not very forthcoming about exactly what probiotics (or prebiotics) they used in their study, similarly just mentioning Bifidobacterium strains, but not specifying which ones. Which makes sense since it appears the CUHK medical school has applied for patents for their probiotic formula in China and the U.S.

Meanwhile, the lead author of the Canadian PROVID-19 study had this to say: “The first step is to demonstrate that probiotics are beneficial for COVID-19 patients. If they are effective, even partially, their low cost and accessibility will greatly facilitate their dissemination.” Of course, they too may not tell us which species they used, if there is a potential patent in their future as well.


Without more detailed data it is hard to know which probiotics work best against COVID-19, but there is one approach we can take: we can use prebiotics. We know the CUHK study included a prebiotic along with their Bifidobacterium strains. And we know that prebiotics, along with spore-based products like LactoSpore, nourish and rebuild each individual’s ideal microbiome.  Prebiotic options include inulin (derived from chicory root), hydrolyzed guar gum (the best choice for those on a Low FODMAP, or SIBO, diet), acacia fiber, and wheat dextrin (partially hydrolyzed wheat starch).

In a study that compared inulin, hydrolyzed guar gum (PHGG), and wheat dextrin (WD), it was determined that WD produced less gas and is better tolerated at higher doses than inulin and PHGG. However, all these fibers were found to “stimulate the growth of Bifidobacteria or Lactobacillus” . (Study) Which is what we are looking for here.

Given the difficulty in getting probiotic supplements to colonize very much in healthy people (see this blog for more on the subject), the best idea is to use LactoSpore, along with a prebiotic fiber, and to include a good amount of fermented foods in the diet. With this approach, we increase all of our good bacteria which are in low supply, as well as create bacteriocins that help keep bad bacteria in check.

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