This poster was presented at The American College of Gastroenterology #ACG2023 conference.
The poster shows that the proportion of Bifidobacterium spp in the stool increases after Ivermectin treatment. Although this is a poster, and room for information in this format is much more limited than a research paper, some specific methodology details appear to be missing, and some potentially flawed arguments are given. Several of these points I will raise below have also been raised for the now-retracted hypothesis Front. Microbiol. (2022) paper by the same first author titled ‘Microbiome-Based Hypothesis on Ivermectin’s Mechanism in COVID-19: Ivermectin Feeds Bifidobacteria to Boost Immunity’ – DOI: 10.3389/fmicb.2022.952321.
Bacterial species in the same genus are not automatically symbionts
The authors state that ‘Bifidobacterium is a member of the same phylum as Streptomyces spp., suggesting it may have a symbiotic relation with Streptomyces’ – this is an unexpected argument that suggests that bacteria in the same phylum might often form symbiotic relations with each other. I cannot think of any example, but perhaps the authors can clarify? Rather, it seems more logical to expect bacteria in the same taxon to compete with each other, since they might share similar metabolic enzymes and pathways. Following the same logic as used by the authors, one could also argue that Mycobacterium tuberculosis or Corynebacterium diphteriae, two known pathogens, may work in synergy with Bifidobacterium spp. There seems to be little scientific foundation for this symbiosis argument. In fact, Ivermectin actually has been shown to inhibit the growth of certain Mycobacterium tuberculosis strains (see e.g. Lim et al (2013), DOI: 10.1128/AAC.01696-12).
Incorrect claim of novelty
The authors write that ‘Although its role as an antiparasitic drug is well established, no studies have shown it’s [sic] effect on the microbiome.’ This statement appears to ignore previous work done by Schneeberger et al. (2018), DOI: 10.1016/j.ijpddr.2018.07.001, who found that IVM caused an increase in Prevotellaceae in the human gut microbiome, while He et al. (2018) showed that Ivermectin+Fenbendazole disturbed the gut microbiome in tigers (DOI: 10.1016/j.bbrc.2018.03.158), Ma et al. (2023) found small effects on the gut microbiome of chinchillas (DOI: 10.3390/vetsci10020169), and Caetano Andrade Belo (2023) found that Ivermectin changed the gut microbiome composition in mice (DOI: 10.1016/j.micinf.2022.105080).
Unclear reasons for ivermectin use
The methods do not clarify why patients received Ivermectin. They write ‘As part of a study on the gut microbiome from September 2020 to August 2021, subjects taking ivermectin as prescribed by their primary care physician for various conditions underwent gut microbiome analysis.’ Given the time period, Ivermectin was most likely prescribed to treat COVID-19 infections. Can the authors please clarify what the other ‘various conditions’ were?
How sick were the patients when they were starting the ivermectin? Were they still sick after they finished their final dose? Could the effect on the gut microbiome composition be solely explained by ivermectin, or could the composition changes also have been the result of e.g. clearance of the virus or getting better in general?
Unclear baseline and demographics
The authors write that stool was collected before ivermectin use, but it is not clear how long before. Can they please clarify at what time relative to the ivermectin course the baseline stool was obtained? In addition, what were the ages of the subjects? Bifidobacteria are often found at higher levels in infants and children, so this might be a relevant piece of data to share.
Potential incorrect conclusion
In the conclusion, the authors write ‘our study offers a new perspective on ivermectin’s mechanisms of action. Given that some viral infections are associated with decreased Bifidobacterium levels, increasing the intestinal population of Bifidobacterium may be a mechanism through which ivermectin exerts its antiviral properties’. First, can they please explain here what the mechanism of action might be? They measure an effect on a small number of genera in a small number of patients, but there is no data provided on the mechanism of action of the drug. There is no mention otherwise about Ivermectin’s antiviral properties, and there is no data suggesting that the measured Bifidobacterium increase is the mechanism of action of ivermectin. It could just be a side effect.
Conflicts of interest
A poster might not have a lot of room for disclosing conflicts of interest, but it might have been nice to include that Dr. Hazan/Progenabiome appear to be selling ‘BiomeBoosters’ (https://biomeboosters.com/) to ‘improve your gut flora and over all immune system wellness’, and that she has several patents related to preventing and treating COVID-19 infections.