Medical journal retracts and republishes study on Long COVID treatments

The journal Annals of Internal Medicine retracted a clinical trial paper on treatments for Long COVID after discovering that the authors omitted dosing information for the diabetes drug metformin, Retraction Watch reported. The journal republished a revised version addressing the omission on the same day as the retraction, 15 October 2026. Long COVID is a chronic condition marked by symptoms persisting weeks, months, or years after a SARS-CoV-2 infection. [1][3]

The editor in chief of Annals of Internal Medicine described the exclusion of the dosing data as sloppy and inaccurate, according to Retraction Watch. The original clinical trial, published in March 2026, investigated therapies for Long COVID, which is a condition that affects an estimated 6 percent of adults at some point, based on population surveys. [1][5]

The trial found that the antidepressant drug fluvoxamine, marketed under the brand name Luvox, reduced fatigue in patients, Retraction Watch reported. However, the study observed that metformin showed no significant benefit in treating Long COVID symptoms. [1]

Despite the publication of the updated study, one researcher told Retraction Watch that the replacement paper still leaves unanswered questions regarding the trial. Persistent symptoms of Long COVID remain a subject of active research, with meta-analyses showing rates up to 36 percent in post-infection cohorts. [1][5]