COVID-19 and Pulmonary Embolism: The Hidden Connection You Need to Know

Introduction

When the COVID-19 pandemic first emerged, the world focused on symptoms like fever, cough, and difficulty breathing. However, as doctors and researchers studied the virus more closely, they uncovered a disturbing truth: COVID-19 doesn’t just attack the lungs — it can wreak havoc on the entire body. One of the most dangerous complications linked to the virus is pulmonary embolism (PE), a condition where blood clots block arteries in the lungs.

Why does this matter? Because pulmonary embolism isn’t just another complication — it’s a potentially life-threatening condition that requires immediate medical attention. Research shows that up to 1 in 4 hospitalized COVID-19 patients may develop pulmonary embolism, especially those in critical care. That means millions of people worldwide have faced this silent threat without even realizing it.

This article breaks down the relationship between COVID-19 and pulmonary embolism in clear, practical terms. We’ll explore how the virus affects your body, why blood clots form, what warning signs to watch for, and what steps you can take to protect yourself. Whether you’ve had COVID-19, are currently fighting an infection, or simply want to understand your risks, this guide will give you the knowledge you need.

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Understanding COVID-19 and Its Effects on the Body

COVID-19 is caused by the SARS-CoV-2 virus, which spreads primarily through respiratory droplets when someone coughs, sneezes, or talks. At first, many people assumed it was “just another respiratory illness.” But as the months went on, it became clear that COVID-19 is far more complex.

For some people, symptoms are mild or even nonexistent. Others experience classic respiratory problems like cough, fever, shortness of breath, or pneumonia. But what makes COVID-19 especially dangerous is its ability to affect multiple organ systems. Beyond the lungs, the virus can damage the heart, kidneys, nervous system, digestive tract, and especially blood vessels.

Here’s why that matters:

• Inflammation Everywhere: COVID-19 triggers the body’s immune system in a way that sometimes spirals out of control. Instead of fighting only the virus, the immune system creates widespread inflammation that injures healthy tissues.
• Blood Vessel Damage: SARS-CoV-2 can directly infect the inner lining of blood vessels (called the endothelium), making them sticky and prone to clotting.
• Long-Term Problems: Even after the initial infection clears, many people suffer from “long COVID,” with symptoms ranging from fatigue and chest pain to brain fog and heart palpitations.

Imagine your body as a busy city. Normally, blood flows like traffic on highways, delivering oxygen and nutrients. COVID-19 is like a sudden flood that not only slows traffic but also damages the roads and causes dangerous pileups. These “pileups” can become blood clots — and if they break loose, they can travel to the lungs, causing pulmonary embolism.

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What Is Pulmonary Embolism?

A pulmonary embolism (PE) happens when a blood clot blocks an artery in the lungs. Most of the time, these clots start in the deep veins of the legs or pelvis — a condition known as deep vein thrombosis (DVT). If a piece of the clot breaks free, it can travel through the bloodstream until it lodges in the lungs.

Here’s what makes pulmonary embolism so dangerous:

• Oxygen Supply Blocked: The clot prevents blood from reaching lung tissue, which reduces oxygen delivery to the rest of the body.
• Small vs. Large Clots: Tiny clots may cause mild or even unnoticed symptoms, but larger clots can be fatal within minutes if not treated.
• Common Symptoms: Sudden shortness of breath, sharp chest pain (especially when breathing deeply), rapid heart rate, dizziness, or even coughing up blood.

In fact, pulmonary embolism is the third leading cause of cardiovascular-related deaths in the United States, after heart attacks and strokes. Without treatment, nearly 1 in 3 people with PE die, but with prompt medical care, survival rates improve dramatically.

Think of it like this: if the body is a house, the bloodstream is the plumbing system. A pulmonary embolism is like a massive clog blocking water flow to the kitchen. Without water, the whole system suffers — and in the body, without oxygen-rich blood, organs can quickly fail.

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The Connection Between COVID-19 and Pulmonary Embolism

So, how exactly does COVID-19 increase the risk of pulmonary embolism? Researchers across the globe have been studying this link since the early months of the pandemic.

• A study published in The Lancet showed that COVID-19 patients have much higher rates of pulmonary embolism compared to patients hospitalized for other reasons.
• Swedish researchers, analyzing more than a million COVID-19 cases, confirmed that the virus itself — not just hospitalization or immobility — is an independent risk factor for blood clots.
• A meta-analysis in the journal Chest revealed that hospitalized COVID-19 patients are far more likely to develop venous thromboembolism (which includes both DVT and PE) compared to non-COVID patients.

Why does this happen? Scientists believe it comes down to three main factors:

1. Endothelial Dysfunction: COVID-19 damages the inner lining of blood vessels, making them more likely to form clots.
2. Hypercoagulability: The infection makes the blood unusually prone to clotting — almost as if the body’s “clotting switch” is stuck in the “on” position.
3. Inflammatory Storm: Severe cases of COVID-19 trigger a “cytokine storm,” an overreaction of the immune system that fuels both inflammation and clotting.

The American Heart Association has gone as far as to say that blood clots are one of the defining complications of severe COVID-19. This means that pulmonary embolism isn’t a rare side effect — it’s a common and very real risk for many patients.

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How COVID-19 Triggers Blood Clots

To understand how COVID-19 triggers pulmonary embolism, you have to picture the body’s natural defense system. Normally, blood clotting is a good thing — it stops bleeding when you get a cut. But in COVID-19, the clotting system goes haywire.

Here’s how it unfolds:

• Endothelial Damage: The virus attacks the endothelium, the protective inner lining of blood vessels. Once damaged, this lining exposes tissues that activate clotting.
• Clotting Imbalance: COVID-19 increases clotting factors while decreasing natural anticoagulants, tipping the balance toward dangerous clot formation.
• Inflammation: Inflammatory cytokines act like accelerators, pushing the clotting process into overdrive.
• Hospitalization Risks: Patients in the hospital, especially those on ventilators, often remain immobile for long periods. Add dehydration and certain medications, and the risk of clots climbs even higher.

A real-world example: Imagine a 55-year-old man hospitalized with severe COVID-19. He spends days in bed on oxygen support. His blood is already in a hypercoagulable state due to the virus. Without preventive measures, he faces a dramatically increased chance of developing DVT, which could travel to his lungs as pulmonary embolism.

This explains why doctors often prescribe blood thinners preventively for COVID-19 patients in hospitals. It’s not just a precaution — it’s a life-saving measure.

Risk Factors for Pulmonary Embolism in COVID-19 Patients

Not everyone with COVID-19 faces the same risk of developing pulmonary embolism. Some groups are far more vulnerable due to a mix of biological, medical, and lifestyle factors. Understanding these risk factors is crucial because it helps patients and doctors stay alert to warning signs and take preventive measures early.

1. Severity of COVID-19 Infection

The more severe the COVID-19 infection, the higher the risk of blood clots. Studies consistently show that patients requiring hospitalization — especially those in the intensive care unit (ICU) — face dramatically higher rates of pulmonary embolism compared to people with mild cases managed at home.

For example, patients on ventilators may be immobilized for days or weeks, which slows blood circulation and creates a perfect setup for clot formation.

2. Gender and Age

Men appear to be at a slightly higher risk of pulmonary embolism when infected with COVID-19 compared to women. Age also plays a significant role. Older adults, particularly those over 65, are more vulnerable because their blood vessels and immune systems naturally weaken over time.

3. Pre-Existing Medical Conditions

Certain chronic conditions increase clotting risks:

• Obesity: Extra body weight puts pressure on veins, slows circulation, and contributes to systemic inflammation.
• Diabetes: Damages blood vessels and interferes with normal clotting balance.
• Heart Disease: Pre-existing cardiovascular conditions already strain the circulatory system.
• Cancer: Many cancer patients are already at elevated risk of clotting, and COVID-19 compounds that danger.

4. Medications and Anticoagulants

Interestingly, patients already taking blood thinners for other medical reasons (such as atrial fibrillation or prior clotting disorders) often show some protection against COVID-19-related pulmonary embolism. This observation has shaped preventive treatment strategies for hospitalized patients.

5. Immobility and Dehydration

Being confined to bed, either at home or in the hospital, slows blood circulation, which can lead to clot formation in the legs (DVT). Add dehydration, which makes blood thicker, and the risk skyrockets.

👉 Key Takeaway: If you or a loved one are hospitalized with COVID-19, be extra vigilant about pulmonary embolism risk, especially if multiple risk factors apply.

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Prevention Strategies

The best way to manage pulmonary embolism in the context of COVID-19 is to prevent it from happening in the first place. Prevention involves a mix of medical treatment, lifestyle adjustments, and practical daily habits.

1. COVID-19 Vaccination

Getting vaccinated and staying up to date with boosters reduces the risk of severe infection, which in turn lowers the chances of clotting complications. Vaccines don’t just protect against catching the virus — they help prevent hospitalization and the cascade of clotting risks that come with it.

2. Medical Prevention in Hospitals

For patients admitted to hospitals with COVID-19, doctors often implement prophylactic anticoagulation protocols. This means prescribing low-dose blood thinners, such as heparin, to prevent clot formation before it becomes life-threatening.

The National Institutes of Health (NIH) has guidelines that help doctors decide which patients should receive preventive anticoagulants, balancing clotting risk against bleeding concerns.

3. Staying Mobile

Even small movements can make a big difference. Gentle stretching, leg exercises, or simply shifting position every 1–2 hours helps keep blood flowing. Patients recovering at home should avoid sitting or lying in one position for too long.

4. Staying Hydrated

Dehydration thickens the blood, increasing clot risk. Drinking adequate fluids — especially water — keeps blood flowing smoothly and reduces clot formation.

5. Compression Stockings

For some high-risk patients, compression stockings help by applying gentle pressure to the legs, promoting circulation and reducing the chance of DVT. However, this should only be used under medical guidance.

6. Lifestyle Habits

Long-term prevention involves maintaining a healthy weight, quitting smoking, and staying physically active. Even light activities like walking can dramatically reduce clotting risk over time.

Think of prevention like building a strong defense system. If pulmonary embolism is the “enemy,” then vaccination, mobility, hydration, and healthy habits are the “shield” protecting you from harm.

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Treatment Options for COVID-19-Associated Pulmonary Embolism

Despite best efforts, some COVID-19 patients still develop pulmonary embolism. In these cases, early diagnosis and rapid treatment are critical for survival and recovery.

1. Anticoagulation Therapy

The first line of defense is anticoagulation (blood-thinning) medication. Doctors often start with heparin-based drugs, delivered through injections or IV drips, because they act quickly. Over time, patients are transitioned to oral anticoagulants like warfarin or newer drugs (DOACs) for ongoing management.

Anticoagulants prevent existing clots from growing larger and stop new ones from forming, giving the body time to naturally break down clots.

2. Balancing Risks

In critically ill patients, doctors must carefully balance the benefits of anticoagulation with the risk of excessive bleeding. COVID-19 patients often receive multiple medications, making drug interactions another challenge.

3. Advanced Interventions

For severe cases, doctors may turn to more aggressive treatments:

• Thrombolytic Therapy: Uses powerful medications to dissolve clots quickly, typically reserved for massive pulmonary embolisms.
• Surgical Embolectomy: In rare cases, surgeons physically remove clots from the lungs.
• Inferior Vena Cava (IVC) Filters: Tiny devices implanted in the large vein that carries blood from the legs to the heart, designed to catch clots before they reach the lungs.

4. NIH Guidelines on Screening

The NIH advises against routine screening for blood clots in all COVID-19 patients because not everyone is at high risk. Instead, doctors focus on patients showing specific symptoms or scoring high on clinical risk assessments.

5. The Role of Diagnostic Tools

Early detection dramatically improves survival rates. Diagnostic steps include:

• D-dimer Tests: Measure clotting activity in the blood, though levels are often elevated in COVID-19 patients in general.
• Imaging Studies: CT pulmonary angiography is the gold standard for confirming pulmonary embolism.
• Clinical Scoring Systems: Tools like the Wells Score help doctors estimate the likelihood of pulmonary embolism.

👉 Real-world insight: Doctors often describe pulmonary embolism as a “time-sensitive emergency.” The sooner treatment starts, the better the outcome. That’s why awareness of symptoms and immediate medical evaluation are so important.

Recognizing Warning Signs

One of the biggest challenges with pulmonary embolism in COVID-19 patients is that the symptoms often overlap with the infection itself. This makes it harder for patients, families, and even healthcare providers to recognize when a blood clot has formed.

1. Breathing Difficulties

Shortness of breath is common with COVID-19, but pulmonary embolism often causes a sudden worsening of breathing problems. If you’re recovering from COVID-19 and suddenly feel breathless walking across a room — when you weren’t before — that’s a red flag.

2. Chest Pain

Pulmonary embolism chest pain usually:

• Feels sharp or stabbing
• Gets worse when taking deep breaths or coughing
• May feel different from the dull, heavy chest pressure some people experience with COVID-19 itself

3. Rapid or Irregular Heartbeat

If your heart suddenly races or feels like it’s skipping beats, especially when combined with breathing difficulties, it could signal that your lungs aren’t getting enough oxygen due to a clot.

4. Coughing Up Blood

Although less common, coughing up even small amounts of blood is a serious warning sign that should never be ignored.

5. Leg Symptoms

Since many pulmonary embolisms start as DVT, watch for:

• Swelling in one leg
• Pain or cramping in the calf
• Warmth or redness along a vein

6. Subtle or Overlapping Symptoms

Some symptoms can be vague: fatigue, dizziness, or lightheadedness. Others may be dismissed as “just COVID.” That’s why any sudden or unexplained change in symptoms should prompt immediate medical evaluation.

👉 Key advice: If you’re recovering from COVID-19 and develop sudden shortness of breath, chest pain, or leg swelling, call emergency services immediately. Pulmonary embolism is a medical emergency where every minute counts.

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Long-Term Implications and Recovery

The story doesn’t always end when the clot is treated. For many COVID-19 survivors, pulmonary embolism has lasting effects on health and quality of life.

1. Post-Pulmonary Embolism Syndrome

Some patients continue to struggle with:

• Persistent shortness of breath
• Chest discomfort
• Fatigue
• Reduced exercise tolerance

This condition, known as post-PE syndrome, may last for months or even years.

2. Recovery Timeline

• Mild PE: Patients may recover within weeks with proper treatment.
• Severe PE: Recovery can take months, especially if lung tissue was damaged.
• Chronic Complications: In rare cases, clots leave behind scar tissue that narrows lung arteries, causing chronic thromboembolic pulmonary hypertension (CTEPH) — a serious, long-term condition.

3. Ongoing Treatment

Most patients require anticoagulation therapy for at least three months. Some, particularly those with ongoing risk factors, may need longer-term or even lifelong blood thinners.

4. Lifestyle Adjustments

Recovery often involves gradual increases in activity. Patients may need pulmonary rehabilitation, which combines exercise training, education, and breathing strategies to help rebuild strength and lung function.

5. Mental and Emotional Impact

Surviving a pulmonary embolism can be emotionally overwhelming. Many patients report lingering anxiety, especially about recurrence. Support from healthcare teams, counseling, and patient support groups can be invaluable in regaining confidence.

👉 Real-world insight: Doctors emphasize that recovery is highly individual. Two patients with the same size clot may have very different experiences based on age, overall health, and other medical conditions.

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The Relationship Between Long COVID and Clotting Risk

One area still being actively studied is how long the clotting risk persists after the initial COVID-19 infection.

• Some studies suggest an elevated risk of pulmonary embolism may last weeks to months after recovery.
• Long COVID patients often report lingering fatigue, chest pain, or breathing difficulties, which may overlap with post-PE symptoms.
• Researchers are exploring whether certain patients might benefit from extended preventive anticoagulation therapy even after they leave the hospital.

The takeaway? If you’ve had severe COVID-19, ongoing monitoring for clotting complications may be necessary even after you start feeling better.

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Frequently Asked Questions

1. What is the life expectancy after pulmonary embolism?

Life expectancy depends on many factors, including the severity of the clot, how quickly it was treated, and overall health. Doctors often use scoring systems to estimate short-term risk:

• Low-risk patients: Only about 1–6% mortality within 30 days.
• High-risk patients: Mortality rates can reach 10–25% if the clot is massive or treatment is delayed.
  With prompt treatment, most people go on to live normal lives.

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2. What are the chances of surviving a blood clot in the lung?

Without treatment, pulmonary embolism can be deadly in about 30% of cases. But with proper medical care, survival improves dramatically — with death rates dropping to 2–8%. Massive clots are more dangerous, with about 1 in 4 acute massive cases causing sudden death.

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3. Are blood clots in the lungs common with COVID-19?

Yes. Multiple studies have confirmed that hospitalized COVID-19 patients face pulmonary embolism rates between 17–25%, far higher than typical hospital patients. ICU patients and those with severe disease have the highest risks.

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4. Can you fully recover after a pulmonary embolism caused by COVID-19?

Many people do recover fully, especially if the clot was detected early and treated promptly. However, some patients develop long-term complications like post-PE syndrome or pulmonary hypertension. Staying consistent with medications, follow-up visits, and lifestyle changes is key to recovery.

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5. How can I reduce my risk of blood clots if I get COVID-19?

• Stay up to date with vaccinations and boosters.
• Stay hydrated and move regularly, even if you’re sick at home.
• Know your risk factors (obesity, diabetes, heart disease, immobility).
• Seek immediate medical attention if you notice sudden shortness of breath, chest pain, or leg swelling.

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Taking Action for Your Health

The connection between COVID-19 and pulmonary embolism is more than a medical curiosity — it’s a serious health risk that has already affected millions worldwide. The good news? With awareness, prevention, and timely treatment, outcomes can be greatly improved.

If you’ve had COVID-19, especially a severe case requiring hospitalization, don’t ignore ongoing symptoms. Talk to your doctor about clotting risks, monitoring, and whether preventive strategies might be appropriate for you.

And remember — prevention is always better than cure. Protect yourself with vaccinations, healthy lifestyle choices, and by staying alert to warning signs. If something feels wrong, trust your instincts and seek medical help right away.