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Aspirin can help prevent blood clots, something that can affect people hospitalized with COVID-19. Grace Cary/Getty Images
  • Researchers say aspirin may help people hospitalized with COVID-19, because of the drug’s abilities to reduce the risk of blood clots.
  • Experts say the study is promising, but more research needs to be done.
  • Experts point out that aspirin is not a preventive medicine and can cause side effects such as excessive bleeding.

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.

A daily dose of aspirin may help reduce the risk of serious complications from COVID-19.

That’s according to researchers from the University of Maryland School of Medicine.

The researchers examined the records of 412 adults with COVID-19 who were admitted to hospitals across the United States between March and July.

Slightly more than 23 percent of the people who were studied were given a daily low dose of aspirin within 24 hours of their admission to the hospital or in the 7 days prior to their admission.

The researchers reported that people taking aspirin were 44 percent less likely to be put on a ventilator and 43 percent less likely to be admitted to the intensive care unit (ICU).

The researchers also reported that those who took aspirin had a 47 percent decrease in risk of dying from COVID-19 when compared with those studied who were not taking a daily dose of aspirin.

“Our analysis suggests that aspirin use may have beneficial effects in patients with COVID-19,” the study authors wrote in their study.

“The results of our study are intriguing, especially because aspirin has been thoroughly studied in chronic cardiovascular disease, has a well-described safety profile, and is readily available throughout the world,” they added.

The researchers argue the findings of their retrospective, observational study warrant further investigation in a randomized controlled trial.

Dr. Dean Blumberg, head of pediatric infectious diseases at the University of California, Davis, says the findings of the study are promising but need to be confirmed.

“It’s interesting, and there’s reason to believe it makes sense because we know COVID-19 induces a hypercoagulable state (increased risk of blood clotting) and that patients have had complications related to blood clots,” Blumberg told Healthline. “That being said, this study is an observational study, so it wasn’t a randomized, double-blind, placebo-controlled trial. So, I would interpret this as promising; I don’t know that I would change practice on the basis of this.”

Should the results be confirmed through further studies, Blumberg says, the findings could assist in outpatient treatment options.

“It would be nice to have something that would be available on an outpatient basis to prevent complications for those who are at lower risk but still at risk for complications, so this could be something that could be incorporated for outpatient treatment protocols,” he said.

“It’s possible that the anticoagulation that is more aggressive than aspirin, maybe that’s not needed, and obviously the more aggressive anticoagulation you give, this could result in tipping the balance so the patient will actually have bleeding complications. So, something milder like aspirin may result in less complications,” Blumberg added.

People with COVID-19 are at an increased risk of blood clots, particularly if they are in the ICU.

Some studies suggest between 30 percent and 70 percent of people with COVID-19 in the ICU will develop blood clots in the legs or lungs.

“This is part of the inflammatory response and… involves the lining of blood vessels, particularly small, medium-sized blood vessels,” explained Dr. William Schaffner, an infectious disease expert at Vanderbilt University in Tennessee. “When that happens, the blood that flows through, it gets a little bit sluggish and begins to clot; and when that happens, that’s not good because the tissues supplied by those blood vessels are deprived of oxygen, and if the clots are in sufficiently large vessels, they can break off and cause strokes and heart attacks.”

Aspirin could be useful as an anti-inflammatory drug that could lessen the body’s inflammatory response to COVID-19 as seen in phase two of the illness, Schaffner told Healthline.

But it can’t be used to prevent the virus.

“It would constrain the overly exuberant inflammatory response that causes the most severe part of the illness, and that occurs in phase two of the illness,” said Schaffner. “It has nothing to do, we’re sure, with inhibiting the virus itself, and that’s the phase one of the illness. So it wouldn’t be something we could use ‘prophylactically’ or as a preventive but as an early therapeutic agent.”

Aspirin works by reducing the clumping action of the blood’s clotting cells known as platelets.

This helps prevent blood clotting and causing blockages that can result in cardiac events or stroke.

Aspirin is commonly used to reduce pain and inflammation. At a low dose, it can also assist in maintaining cardiac health.

“There’s no question that aspirin is probably one of the more important drugs that we have in terms of treating and reducing secondary events,” Dr. Dean Winslow, an infectious disease specialist at Stanford University in California, told Healthline.

“Aspirin is a drug that has been around for well more than 100 years, and in the last 40 years, we have certainly taken advantage of its effects both as an anti-inflammatory agent and its direct effect on inhibiting platelet function to reduce these vascular events,” he added.

But aspirin isn’t without its side effects.

Winslow says more research is needed before aspirin is regularly used in people with COVID-19.

“I certainly wouldn’t recommend that everybody just start taking aspirin, because if you look at people who are otherwise healthy, you may end up with more complications, including gastrointestinal bleeding and other things like that. The risks may potentially outweigh the benefits,” Winslow said.

All the experts who spoke with Healthline emphasize that although the results of this small study are promising and warrant further investigation, aspirin will not be a silver bullet that will protect the population from developing COVID-19.

“This doesn’t prevent you from catching COVID-19. Until we get an effective vaccine, we need to absolutely emphasize the point that prevention, prevention, prevention are the three most important things, and that means social distancing, wearing face coverings, avoiding crowded indoor environments,” Winslow said.

Blumberg argues that although there is yet to be a preventive medication or vaccine against COVID-19, it doesn’t mean we don’t have proven options to protect the population.

“We have proven preventative options and that’s social distancing and wearing masks — those are proven to work and to prevent infection. In terms of medications that will do that, we don’t have those yet,” he said.

But until there is further investigation in the form of a prospective controlled, double-blind trial, Schaffner advises against premature excitement.

“There was a lot of enthusiasm about hydroxychloroquine. It looked so great. Everybody was very excited. Many of us, myself included, were very hopeful,” he said. “Then, of course, the very rigorous, prospective controlled trials showed us that our enthusiasm was, shall we say, a little bit early because it didn’t work out. So, we need to address the hard realities, and they will be revealed by a rigorous prospective controlled trial.”