About The Study

This pilot study aimed to determine if taking a probiotic in combination with antiretroviral therapy (ART) could help reduce inflammation and harmful immune activation in those who don’t respond completely to ART.

Probiotic products are live bacteria that may provide health benefits and are often referred to as “beneficial” bacteria. The specific probiotic used in this study, Visbiome, is approved by Health Canada as a Natural Health Product. However, its use in this research study was experimental.


Approximately 25% of HIV-infected individuals who start taking ART have a sub-optimal response meaning that their immune system (CD4 count) doesn’t improve as expected, even though the virus is suppressed by their medications. These individuals are sometimes known as immune non-responders (INRs). These individuals are at increased risk of AIDS-related deaths and non-AIDS related health problems that may be associated with increased immune activation and leaking of bacteria from the gut into the bloodstream.

Consistent use of ART to manage HIV is known to extend life expectancy by many years. However, many people living with HIV have more inflammation and immune activation-related health conditions (like heart and brain diseases) compared with uninfected people, even after taking ART for a long period of time. This is a result of bacteria entering the bloodstream through a person’s gut lining, which has been damaged by HIV. Although ART has drastically improved HIV care, it can take years of continuous ART to repair HIV-related damage to the immune cells in the gut.

This study investigated whether taking a probiotic would fix the damage to gut tissue or improve the response to ART in INRs. There is considerable evidence that a change in the balance of beneficial and harmful bacteria can influence gut immune health. For example, beneficial bacteria have been shown to enhance the ability of immune cells to fight harmful bacteria. The study tested whether this probiotic might improve the function and number of healthy immune cells in the gut, prevent bacterial leakage into the bloodstream and ultimately reduce the inflammation that causes HIV-related health complications in INRs.

Study Approach

The duration of the study was 48 weeks. The study was double-blinded, meaning that neither the participants or their doctor knew which treatment group they were in.

  • Probiotic treatment group: Probiotic Visbiome (two sachets daily) + standard ART
  • Control treatment group: Placebo (two sachets daily) + standard ART. The placebo had no active ingredient but looked the same as Visbiome.

Bloodwork and questionnaire material were collected periodically throughout the course of the study. This information was used to compare immune function, inflammation, and gut health between the two study groups.


While the treatment regimen of probiotic combined with standard ART was safe and well tolerated among the participants, it did not reduce inflammation or harmful immune activation in the bloodstream. Furthermore, it had no detectable effects on gut immune function. Supplementation with probiotics may have other health benefits, but CTNPT 022b concluded that there is no need to continue investigating the potential for this probiotic to reduce harmful inflammation in immune non-responders who are already on effective ART.

Eligibility Requirements


  • Documented HIV-1 infection
  • Male and 18 years or older
  • Currently on ART (more than 2 years)
  • Undetectable HIV-1 viral load <50 copies/ml for the past 2 years
  • CD4 count must be <350 cells/ul at least 70% over the past 2 years
  • Ability to provide informed consent

Not Allowed

  • Current alcohol or substance use judged by the Investigator to potentially interfere with the participant’s study compliance
  • Taking pharmaceutical grade probiotics
  • Laboratory results in screening deemed abnormal for the purposes of this study
  • Significant underlying disease (non-HIV-1) that might impact disease progression or death

For a full list of eligibility criteria, visit clinicaltrials.gov.

Additional Information

If you would like more information on this clinical study, please refer to a participating site.

Principal Investigator

Here’s who is leading this study.

Can’t find what you’re looking for? Email ctninfo@hivnet.ubc.ca.

Participating Sites

Here’s where this study is being conducted.