Should I Take Baby Aspirin After COVID?

No major medical guideline currently recommends taking baby aspirin (low-dose, 81 mg) specifically because you had COVID-19. The idea has a logical appeal: COVID is well known to trigger abnormal blood clotting and inflammation, and aspirin counteracts both. But the clinical evidence connecting that biological rationale to real benefits after you leave the hospital or recover at home is surprisingly thin. For most people who have recovered from a COVID infection, starting aspirin on your own is more likely to carry risk than clear benefit.

Why the Idea Sounds Reasonable

COVID-19 is not just a lung disease. The virus triggers an intense inflammatory response that reaches deep into the blood vessels and the clotting system. Research has consistently found that COVID patients show markers of endothelial damage (injury to the lining of blood vessels), heightened thrombin generation, and abnormal platelet behavior.¹ Platelets in COVID patients tend to be in a “primed” state, with surface changes that push them toward clotting activity rather than sitting idle. One study found that resting platelets from COVID patients already showed procoagulant features, and their activation correlated directly with markers of inflammation.²

This prothrombotic state explains why hospitalized COVID patients developed blood clots at alarmingly high rates early in the pandemic, from deep vein clots to pulmonary embolisms and even strokes. And the clotting abnormalities don’t always resolve once the acute infection is over. Researchers have identified persistent fibrin-based “microclots” in the plasma of people with long COVID that resist the body’s normal clot-dissolving mechanisms.³ These microclots have been associated with ongoing long COVID symptoms like fatigue and brain fog.⁴

Aspirin, meanwhile, does two things that seem tailor-made for this problem. It irreversibly blocks the enzyme cyclooxygenase (COX) in platelets, which prevents them from producing thromboxane A2, a chemical signal that makes platelets clump together.⁵ On top of that, low-dose aspirin has anti-inflammatory effects. In human experiments, 75 mg daily aspirin reduced the accumulation of immune cells at sites of inflammation and triggered the production of specialized inflammation-resolving molecules.⁶ Lab research has also shown aspirin can prevent inflammation-induced damage to blood vessel linings, though it was less effective at reversing damage already in progress.⁷

Put those two pieces together and you can see why people reach for a baby aspirin after getting COVID. The virus revs up clotting and inflammation; aspirin dials both back. But biological plausibility is not the same as clinical proof, and this is where the story gets complicated.

What the Hospital Evidence Actually Shows

Most of the research on aspirin and COVID has been done in hospitalized patients, not in people recovering at home. A meta-analysis pooling data from studies of hospitalized COVID patients found that aspirin use was associated with about a 16% decrease in in-hospital death.⁸ A large observational study came to a similar conclusion: among patients with moderate COVID, early aspirin use was linked to somewhat lower 28-day mortality and lower rates of pulmonary embolism, without a meaningful increase in bleeding complications.⁹

Those numbers might sound encouraging, but there is an important catch. One narrative review noted that an earlier observational study found aspirin use before hospitalization was associated with roughly halved risks of ICU admission, mechanical ventilation, and in-hospital mortality. However, the same review cautioned that the association with mortality remained “debatable” given the limitations of observational data.¹⁰ When researchers turned to randomized controlled trials, which are the stronger form of evidence, the picture shifted. A systematic review of randomized trials found that aspirin did not significantly reduce rates of blood clots in COVID patients. Looking at specific outcomes, there was no clear reduction in deep vein thrombosis, pulmonary embolism, stroke, or heart attack.¹¹

That disconnect between the observational data (which looked promising) and the randomized trials (which did not) is a red flag researchers know well. People who were already on aspirin before getting COVID tend to be the kind of patients whose doctors actively manage their cardiovascular risk. They might be taking other medications, seeing their doctors more often, or having their conditions monitored more closely. All of that could explain the observed benefit without aspirin itself being the cause.

The Gap After the Hospital

Even if hospital-based aspirin had clear benefits, the question most people are asking is different: should you take a baby aspirin after you have recovered from COVID and are back to your normal life? Here the evidence is almost nonexistent. No major clinical trial has specifically tested whether starting low-dose aspirin after COVID infection reduces the risk of long-term complications like heart attack, stroke, or long COVID symptoms.

Neither the NIH COVID-19 Treatment Guidelines nor the European Society of Cardiology have issued recommendations for aspirin as primary prevention of clotting events during or after the pandemic.¹⁰ That silence is telling. These are organizations that issue guidance rapidly when evidence supports a new intervention. The absence of a recommendation is itself a signal that the data is not there.

There has been one small effort worth mentioning. Researchers tried a “triple anticoagulant” approach for long COVID patients using aspirin, clopidogrel (another antiplatelet drug), and apixaban (a full anticoagulant), along with a stomach-protecting medication.¹² That study was a preprint, had no control group, and used a combination far more aggressive than a single baby aspirin. It generated interest in the long COVID community but fell well short of evidence that could change practice. Nobody should take a triple anticoagulant cocktail based on a preliminary uncontrolled study.

The Bleeding Risk That Tips the Scale

When the potential benefit of a drug is uncertain, the known risks become the deciding factor. For aspirin, the primary concern is bleeding. A systematic review for the U.S. Preventive Services Task Force found that low-dose aspirin (100 mg or less daily) increased the risk of major gastrointestinal bleeding by about 58% and showed a trend toward increased hemorrhagic stroke risk.¹³ In absolute terms, the excess worked out to roughly 1 to 2 additional major GI bleeding events per 1,000 people per year.

Those numbers might seem small, but they accumulate over time. A large long-term study following women over 24 years found that regular aspirin use (two or more standard tablets per week) raised the risk of gastrointestinal bleeding by about 43%, with the risk climbing as the dose increased.¹⁴ A separate systematic review of observational studies estimated the overall relative risk of GI bleeding with low-dose aspirin at around 1.4, and notably found that both upper and lower GI bleeding risks were elevated, along with a similar increase in intracranial hemorrhage risk.¹⁵

For someone who has a clear reason to be on aspirin — a prior heart attack, a stent, established cardiovascular disease — that bleeding risk is worth accepting because the clotting risk without aspirin is high and well-documented. For someone whose only reason is “I had COVID a few weeks ago,” you are adding a real, quantifiable risk of bleeding in exchange for a speculative benefit that no trial has confirmed. That math does not work in your favor.

If You Were Already on Aspirin Before COVID

A different question is whether you should continue aspirin if you were already taking it for a cardiovascular condition and then got COVID. Here the answer is simpler: in general, yes. Stopping a medication your doctor prescribed because you got an infection is rarely a good idea unless a physician tells you otherwise.

Interestingly, one study of COVID patients who already had coronary artery disease found that pre-hospitalization use of low-dose aspirin did not appear to improve outcomes. Mortality was essentially identical between the aspirin group and the non-aspirin group, even among critically ill patients.¹⁶ That does not mean aspirin stopped working for their heart disease — it means it probably was not providing additional protection specifically against COVID’s clotting effects in that population. The takeaway is that you continue aspirin for the reason it was originally prescribed, not as a COVID-specific treatment.

The current U.S. Preventive Services Task Force guidelines on aspirin for primary prevention (meaning for people who have not yet had a cardiovascular event) already take a cautious stance. As of 2022, they recommend a case-by-case decision for adults aged 40 to 59 who have at least a 10% ten-year cardiovascular disease risk, and only for those not already at elevated bleeding risk.¹⁷ Having had COVID does not change these recommendations. If your doctor had not recommended aspirin before your infection, a COVID diagnosis alone is unlikely to be the tipping point.

Who Faces Higher Clotting Risk From COVID

Not everyone’s risk profile after COVID is the same, which complicates any blanket advice. Research on hospitalized COVID patients has consistently found that men face substantially higher rates of both blood clots and death than women. In one large study, the combined outcome of death or thrombosis was more common in men (36% vs. 29%), with the gap being widest in younger adults: men aged 18 to 54 had more than three times the odds of death or clots compared to women of the same age.¹⁸ Another study confirmed these patterns, finding that women had about 30% lower odds of venous clots and about 24% lower odds of arterial clots compared to men. The same study found that non-Hispanic Black patients had higher rates of both venous and arterial clotting events than other groups.¹⁹

These disparities are important context, but they describe clotting risk during acute illness, not after recovery. Whether higher-risk groups benefit from post-COVID aspirin is unknown. What these findings do suggest is that if any post-COVID antiplatelet strategy ever proves effective, it would likely need to be targeted rather than universal, accounting for sex, age, and other individual risk factors. That is another argument against simply starting aspirin on your own — the people who might benefit are not necessarily the same people who think to do it.

Children, MIS-C, and a Narrow Exception

One population where aspirin does have a defined role after COVID is children who develop multisystem inflammatory syndrome (MIS-C), a rare but serious condition that can occur weeks after a COVID infection. MIS-C involves widespread inflammation that can affect the heart, blood vessels, and other organs. Clinical guidance recommends low-dose aspirin (at pediatric dosing of 3 to 5 mg/kg per day, up to 81 mg) for hospitalized MIS-C patients, to be continued for at least one month from diagnosis or longer if coronary artery abnormalities are present.²⁰ Higher aspirin doses and additional anticoagulants are reserved for children with more severe cardiac involvement, such as coronary artery aneurysms or reduced heart function.²¹

MIS-C is a clinically distinct entity from typical COVID recovery, and the aspirin use here is managed by a medical team with specific monitoring. It should not be interpreted as evidence that aspirin is broadly beneficial after COVID. If anything, it illustrates that when clinicians do identify a clear inflammatory and clotting disorder after COVID, they prescribe aspirin in a controlled setting with careful follow-up — the opposite of unsupervised self-medication.

The Self-Medication Problem

The reality is that many people are not waiting for clinical trials to finish. People living with long COVID have reported turning to a wide range of over-the-counter medications, supplements, and dietary changes to manage their symptoms, often without medical guidance. Researchers have flagged this as a concern, noting the risks of harmful drug interactions and use of treatments that have not been evaluated for this condition.²²

Aspirin might seem innocuous because it is cheap, familiar, and available without a prescription. But familiarity masks real risk. People with undiagnosed stomach ulcers, those taking blood thinners or other anti-inflammatory medications, those with uncontrolled high blood pressure, and older adults with higher baseline bleeding risk can all experience serious harm from even low-dose aspirin. The fact that aspirin is available over the counter does not mean it is harmless, and the fact that COVID causes clotting does not mean aspirin after COVID prevents anything useful.

If you are experiencing persistent symptoms after COVID and suspect a clotting problem, the appropriate step is to discuss it with a physician who can order relevant blood work, assess your individual risk, and if warranted, prescribe antiplatelet or anticoagulant therapy with proper monitoring. The treatments being explored in research settings — like the triple anticoagulant protocol mentioned earlier — are aggressive regimens paired with stomach-protecting drugs and physician oversight. They bear no resemblance to tossing a baby aspirin into your morning routine.

What Researchers Are Still Trying to Figure Out

The microclot hypothesis remains one of the more intriguing leads in long COVID research. The observation that fibrin-based deposits persist in the blood of long COVID patients and resist normal breakdown is genuinely unusual.³ Three hypotheses are being explored: that lasting structural damage to blood vessel walls from the initial infection keeps the clotting system activated; that a reservoir of virus persists somewhere in the body and continues to provoke inflammation; and that a misdirected immune response drives ongoing vascular harm even after the virus is cleared.¹

Each of those mechanisms would call for a different treatment approach. If the problem is persistent viral reservoirs, antivirals might help more than aspirin. If the issue is autoimmune-driven endothelial damage, immunomodulatory therapy could be more appropriate. If structural vascular damage is the culprit, healing might require time and rehabilitation rather than antiplatelet drugs. The honest answer is that we do not yet know which mechanism dominates, and until that question is settled, it is difficult to know which drug, if any, would help with post-COVID clotting problems. Aspirin is just one candidate among many, and it may not even be the right category of drug for the underlying problem.

Several clinical trials are underway or recently completed examining various antiplatelet and anticoagulant strategies for long COVID. Until those results mature into guideline-level recommendations, the strongest thing you can say about baby aspirin after COVID is that the rationale is there but the proof is not. For most healthy adults recovering from a typical COVID infection, the known bleeding risk of daily aspirin outweighs an unproven clotting benefit. Talk to your doctor before making it part of your routine.