COVID-19 is a respiratory disease. It can do a lot of damage to your respiratory tract, which includes your lungs.
COVID can cause a range of breathing problems, from mild to critical. Older adults and people with other health conditions like heart disease, cancer, and diabetes may have more serious symptoms.
Here's what COVID does to your lungs.
COVID-19 and Your Lungs
SARS-CoV-2, the virus that causes COVID, is part of the coronavirus family.
When the virus gets into your body, it comes into contact with the mucous membranes that line your nose, mouth, and eyes. The virus enters a healthy cell and uses the cell to make new virus parts. It multiplies, and the new viruses infect nearby cells.
Think of your respiratory tract as an upside-down tree. The trunk is your trachea, or windpipe. It splits into smaller and smaller branches in your lungs. At the end of each branch are tiny air sacs called alveoli. This is where oxygen goes into your blood and carbon dioxide comes out.
COVID can infect the upper or lower part of your respiratory tract. It travels down your airways. The lining can become irritated and inflamed. In some cases, the infection can reach all the way down into your alveoli.
COVID was only identified in 2019, and scientists are learning more every day about what it can do to your lungs. They believe that the effects of COVID on your body are similar to those of two other coronavirus diseases, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).
COVID-19 and Lung Scarring
If you've had a severe case of COVID, you may have lasting lung damage even after you test negative for the virus.
Your immune system creates inflammation as it works to fight off COVID. Some inflammation is normal, but too much can cause scarring in healthy lung tissue. You may hear this scarring called "pulmonary fibrosis."
You're more likely to have lung scarring if you were pregnant, older than 65, unvaccinated for COVID, immunocompromised, or had a history of smoking when you got sick.
How do you know if you have lung scarring? Symptoms include being short of breath or having a lingering cough. Your doctor may screen for scarring with an imaging test like a CT scan or with a bronchoscopy, an exam where your doctor uses a lighted tube to look at your airways.
Unfortunately, lung scarring is often permanent. But your health care team will suggest therapies so you can get the oxygen you need.
Lung Symptoms in Mild and Moderate COVID
As the infection travels through your respiratory tract, your immune system fights back. Your lungs and airways swell and become inflamed. This can start in one part of your lung and spread.
About 80% of people who have COVID get mild to moderate symptoms. You may have a dry cough or a sore throat. Some people have pneumonia, a lung infection in which the alveoli are inflamed.
Doctors can see signs of respiratory inflammation on a chest X-ray or CT scan. On a chest CT, they may see something they call "ground-glass opacity" because it looks like the frosted glass on a shower door.
Severe COVID-19 Lung Symptoms
About 14% of COVID cases are severe, with an infection that affects both lungs. As the swelling worsens, your lungs fill with fluid and debris.
You might also have more serious pneumonia. The air sacs fill with mucus, fluid, and other cells that are trying to fight the infection. This can make it harder for your body to take in oxygen. You may have trouble breathing or feel short of breath. You may also breathe faster.
If your doctor takes a CT scan of your chest, the opaque spots in your lungs may look like they're starting to spread and connect to each other.
Critical COVID-19 Lung Symptoms
In critical COVID, which makes up about 5% of total cases, the infection can damage the walls and linings of the air sacs in your lungs. As your body tries to fight it, your lungs become more inflamed and fill with fluid. This can make it harder for them to swap oxygen and carbon dioxide.
You might have severe pneumonia or acute respiratory distress syndrome (ARDS). In the most critical cases, your lungs need help from a machine called a ventilator to do their job.
There's evidence that 20%-30% of the critically ill patients can develop clots in the lungs, heart, brain, and legs, some of which are life-threatening.
COVID-19 Complications
t can take time to feel better after you have pneumonia. You may feel more tired than usual for a while. You might also find that you can't exercise like you used to.
Some people had a cough even after recovering from COVID. Others had scarring in their lungs. Doctors are still studying whether these effects are permanent or might heal over time. A few people have even needed lung transplants because of severe tissue damage from COVID.
COVID Lung Impact FAQs
How is pneumonia after COVID-19 treated?
If you have pneumonia, your doctor may treat it with a mix of antiviral medications and antibacterial antibiotics. Depending on how severe your case is, you may also need an IV to stay hydrated or supplemental oxygen if you're not getting enough.
What can help improve lung function after COVID-19?
Depending on how severe your COVID case was, you may need to work with a respiratory therapist once you're virus-free to improve your lung capacity. Your respiratory therapist might recommend that you maintain a healthy diet, slowly start cardio workouts, and use an incentive spirometer device to track how deeply you can breathe. When in doubt, practice slow, deep breaths to stay calm and regain lung strength.
