Metformin: a diabetes drug useful to prevent long Covid

A discovery and auspicious tests. Metformin, a diabetes drug that is both cheap and widely available, would reduce the risk of contracting long-term Covid by 40% after testing positive for Covid, according to a study published Friday. The World Health Organization recalls that the still mysterious disease, which drags on over time, affects one in 10 people catching Covid.

A randomized, placebo-controlled phase 3 trial tested metformin. Originally developed from the French lilac flower, it has been the most commonly used treatment in the world to treat type 2 diabetes for decades. This means that it is reputed to be safe, in addition to being inexpensive and widely available.

Encouraging results

The study, published in the journal Lancet Infectious Diseases, involved 1,126 overweight or obese people in the United States, half receiving metformin and the other half a placebo in the days following a positive Covid test. After 10 months, 35 of the participants who had taken metformin were diagnosed with long-term Covid, compared to 58 for the placebo group, representing a 40% reduction in risk. The trial was conducted between December 2020 and January 2022, meaning it included the Omicron variant, which would have caused less Covid lengths than previous strains, the research said.

The team behind the trial had previously shown that metformin reduced the risk of emergency room visits, hospitalizations and patient death by more than 40%. "Our data show that metformin reduces the amount of SARS-CoV-2 virus" in patients, Carolyn Bramante, a researcher at the University of Minnesota and lead author of the new study, told AFP.

If confirmed, these results would be "potentially significant" for long-term Covid research, Jeremy Faust, a Harvard Medical School doctor not involved in the study, said in a comment. Frances Williams, professor of epidemiology at King's College London, notes, however, that 564 people had to take this drug to "avoid 23 hypothetical cases" of long Covid. This means that "24 people took metformin to prevent one case of Covid long".

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The researchers clarified that the drug had not been tested on people already suffering from long Covid, and therefore could not be used to treat this disease but only prevent it. That the antiparasitic drug ivermectin, which has been the subject of misinformation throughout the pandemic, as well as the antidepressant fluvoxamine, had not prevented contracting long Covid.