Large study links semaglutide use to 49% lower COVID-19 mortality risk

A study of more than 10 million people with commercial or Medicare Advantage insurance found something striking: those taking semaglutide, the diabetes and weight-loss drug sold under brand names like Ozempic and Wegovy, had a 49% lower risk of dying from COVID-19 compared to those who did not use the medication. The finding comes from researchers at the University of California, San Francisco, who analyzed pharmacy and medical claims from July 2021 through June 2022, a period when the pandemic was still claiming lives but vaccines were available and the acute emergency had begun to recede into something more chronic.

The result is noteworthy partly because it aligns with earlier findings from a major clinical trial called SELECT, which had suggested a 34% reduction in COVID-19 risk among semaglutide users. But this new work operates in a different register—it draws from the messy, real world of insurance claims rather than the controlled environment of a randomized trial. The researchers had to account for a fundamental problem: people taking semaglutide are not a random sample of the population. They tend to be older, more likely to have diabetes or obesity, and burdened with other serious conditions. All of these factors independently increase the risk of severe COVID-19 and death. So the team used statistical techniques to level the playing field, adjusting for age, existing health conditions, vaccination status, prior infection, and use of other medications that might affect outcomes. After these adjustments, the protective association remained strong.

The raw numbers tell part of the story. Among the roughly 97,000 person-years of observation among semaglutide users, there were 192 COVID-19 deaths. Among the much larger non-user group—nearly 8.7 million person-years—there were 13,591 deaths. On the surface, this looks worse for semaglutide users, but that's because they started from a place of greater vulnerability. The study population was majority white (62%) and female (51%), with a mean age of 47. About 15% had obesity and 13% had diabetes. Nearly one in ten had heart disease. Fewer than 8% had ever had a documented COVID-19 infection, and only 45% had received at least one vaccine dose during the study window.

The researchers proposed several possible explanations for why semaglutide might reduce COVID-19 mortality. The drug is a GLP-1 receptor agonist, a class of medication that appears to have anti-inflammatory properties beyond its primary role in controlling blood sugar and reducing body weight. It might dampen the excessive immune response that sometimes makes COVID-19 severe. It might reduce airway hyperresponsiveness, making the lungs less reactive to viral infection. Or the weight loss itself—semaglutide is effective at helping people shed pounds—might confer protection. But the study did not measure inflammation, lung function, or respiratory symptoms directly. These remain hypotheses, educated guesses that point toward future research.

The authors are careful about what they claim. This is an observational study, meaning it documents an association but cannot prove that semaglutide caused the lower mortality. People who take semaglutide might differ from non-users in ways the data does not capture—their health literacy, their access to care, their adherence to other preventive measures. The confidence interval around the main finding is tight (0.43 to 0.61), suggesting the association is real and not due to chance, but tightness is not the same as causation. The researchers call for randomized controlled trials to settle the question, the gold standard that would randomly assign people to receive semaglutide or placebo and follow them forward in time.

What makes this work significant is its scale and its grounding in actual medical practice. The study examined over 10 million people, not hundreds or thousands. It looked at real prescriptions filled at real pharmacies, real hospitalizations, real deaths recorded in insurance systems. The finding that diabetes and obesity independently doubled and increased by a third, respectively, the hazard of COVID-19 death aligns with what clinicians have long observed—that people with these conditions face steeper odds when they encounter the virus. If semaglutide truly protects against severe COVID-19, it would represent a secondary benefit of a drug already in wide use, a kind of therapeutic bonus. But that remains to be proven. The next step is prospective research, trials that follow people forward and measure not just mortality but the mechanisms that might explain it.