Aspirin showed early promise as a COVID-19 treatment, but the largest clinical trials found it does not reduce the risk of death from the disease. The National Institutes of Health does not include aspirin in its recommended treatment protocols for either hospitalized or non-hospitalized COVID-19 patients. That said, the story is more nuanced than a simple no, and the answer depends on what you’re hoping aspirin will do.
What the Largest Trial Found
The RECOVERY trial, one of the biggest and most rigorous COVID-19 treatment studies ever conducted, randomly assigned nearly 15,000 hospitalized patients to receive either 150 mg of aspirin daily or standard care alone. The result: 17% of patients died within 28 days in both groups, with no meaningful difference. Aspirin also did not reduce the chance of needing a ventilator.
There was one modest benefit. Patients who received aspirin were slightly more likely to be discharged alive within 28 days (75% vs. 74%), and their hospital stays were about a day shorter on average. That’s a real but small effect, and it wasn’t enough for major health agencies to recommend aspirin as a standard COVID-19 treatment.
Why Aspirin Seemed Promising
The biological logic behind aspirin for COVID-19 was sound. Autopsies of patients who died from the disease consistently revealed tiny blood clots, called microthrombi, lodged in the blood vessels of inflamed lung tissue. COVID-19 causes platelets to become hyperactive, triggering both clotting and inflammation at the same time. This process can cascade into widespread organ damage.
Aspirin blocks the production of a chemical that makes platelets clump together, and it also dials down inflammation by inhibiting the same enzymes targeted by ibuprofen. In theory, this dual action could interrupt the dangerous cycle of clotting and inflammation that makes severe COVID-19 so deadly. Aspirin can even interfere with viral replication to some degree by disrupting a key inflammatory signaling pathway in cells.
The problem is that nearly all hospitalized COVID-19 patients already receive blood thinners like heparin, which work through a different and more potent mechanism. Heparin blocks a step further upstream in the clotting process, and researchers believe this likely overshadowed whatever anti-clotting benefit aspirin could add on its own.
Observational Studies Paint a Different Picture
Before the RECOVERY trial reported its results, smaller observational studies had suggested aspirin might cut COVID-19 mortality by roughly 30%. A meta-analysis pooling these studies found that aspirin use was associated with a 31% reduction in death, with low-dose aspirin (typically 75 to 81 mg daily) showing an even stronger association, around a 36% reduction. Studies from Europe and the Americas, and cohort studies in particular, supported this protective signal.
The catch is that observational studies can’t prove cause and effect. People who were already taking daily aspirin before getting COVID-19 may have been under closer medical care for heart disease, or they may have differed from non-users in ways that influenced survival. When the randomized trial, which eliminates those biases, showed no mortality benefit, it carried more weight.
Aspirin for Long COVID Symptoms
A separate line of research has explored whether aspirin could help with long COVID, specifically through the “microclot” theory. Researchers in South Africa identified tiny, hard-to-dissolve clots in the blood of people with persistent symptoms after infection. In a small, uncontrolled study of 24 people with long COVID, a combination of low-dose aspirin, another antiplatelet drug, and a blood thinner led to improvements in symptoms and a visible reduction in microclots.
This is preliminary work. The study had no control group, was not a clinical trial, and has not been peer-reviewed. Larger, properly designed trials are underway to test whether anticoagulant and antiplatelet therapies genuinely help long COVID, but there is no established evidence yet supporting aspirin for this purpose.
Aspirin for COVID Fever and Aches
If you’re thinking of aspirin simply to manage a fever or body aches while sick with COVID-19, there’s a wrinkle worth knowing. Research on rhinovirus infections found that aspirin and acetaminophen both suppressed the body’s antibody response and prolonged viral shedding. In one trial, these fever reducers actually worsened nasal symptoms. Since fever is part of the immune system’s defense against infection, suppressing it in the early stages of a viral illness may not be entirely helpful.
This doesn’t mean you should suffer through a dangerously high fever, but it does suggest that reaching for a fever reducer at the first sign of mild symptoms may not speed your recovery. Acetaminophen and ibuprofen share this same issue, so aspirin has no particular advantage or disadvantage for basic symptom relief in COVID-19.
Never Give Aspirin to Children With COVID
Aspirin should not be given to children or teenagers with any viral illness, including COVID-19. Using aspirin during a viral infection can trigger Reye’s syndrome, a rare but potentially fatal condition that causes swelling in the liver and brain. The risk is highest when aspirin is combined with a viral illness in children who have an underlying metabolic condition called a fatty acid oxidation disorder, but it can occur in otherwise healthy children too. Acetaminophen or ibuprofen are the safe alternatives for managing fever and pain in kids.
The one exception involves a specific complication called multisystem inflammatory syndrome in children (MIS-C), a serious post-infection condition. In that setting, the NIH does recommend low-dose aspirin as part of the treatment plan, but only under direct medical supervision in a hospital.
The Bottom Line on Aspirin and COVID
If you already take daily low-dose aspirin for heart disease or another condition, there’s no reason to stop it because of a COVID-19 infection. But starting aspirin specifically to treat or prevent COVID-19 is not supported by the strongest available evidence. The largest randomized trial found no survival benefit, and health agencies do not recommend it. Aspirin carries its own risks, particularly gastrointestinal bleeding, that make it a poor choice as a general-purpose COVID-19 remedy for people who wouldn’t otherwise be taking it.