Coronavirus: How COVID-19 Affects Your Body

Doctors continue to learn about the short-term and long-term effects of COVID-19 on your body. For some people, it starts with basic flu symptoms. But it could eventually affect your lungs, liver, kidneys, and even your brain.

Usually the virus makes contact with you when a nearby infected person sends droplets into the air by coughing, sneezing, or talking. It spreads easily between people within about 6 feet of each other. An infected person can spread these droplets, even if they don’t feel sick. The virus may infect you after you touch an object, like a doorknob, that has the virus on it. But that's not as common.

Once the virus enters the body, it usually settles in the cells that line your nose, sinus cavity, and throat. For most people, this is where it stays. Symptoms often follow, but you may not feel anything for up to 2 weeks, as the virus starts to invade healthy cells and reproduce. You can transmit it to others even if you don't show any symptoms.

The first symptoms that typically appear include a fever, headache, sore throat, and dry cough. But what you'll feel can vary widely in this early stage. You may also have:

• Shortness of breath
• Chills, fever, body aches
• Loss of sense of smell or taste
• Unusual tiredness
• Stuffy or runny nose
• Nausea or diarrhea

If your immune system can't subdue COVID-19 in the first week or so, the virus may move down into your lungs. There, it attacks cells that line them. Fluid and mucus build up and make it harder to get oxygen to your blood. It gets tough to breathe. This is pneumonia. Most people recover in a week or two, but it can take longer.

In acute respiratory distress syndrome (ARDS), your COVID-19 pneumonia gets worse quickly, and your body's response can damage your lungs more. The tiny, delicate air sacs (called alveoli) that transfer oxygen to your blood start to fill with gunk. X-rays and CT scans can show large parts of your lung getting no air at all. Oxygen levels in your blood get dangerously low, and you'll probably need a ventilator to help you breathe.

Many doctors think an overblown immune response causes many of the more serious consequences of COVID-19. Levels of chemical signaling agents called cytokines get so high that immune cells start to attack healthy tissues. Doctors might call this a cytokine storm. It can lead to things like low blood pressure, organ failure, and blood vessel damage.

Doctors have noticed a number of heart issues in people with COVID-19, especially in those who are seriously ill. These include:

Arrhythmia. A skipping or racing heart

Cardiomyopathy. Your heart gets weaker from thickened, stiffened heart tissue.

Acute cardiac injury. Your body releases high levels of a protein called troponin. This normally happens when your heart is damaged.

Shock. When your heart can't pump enough blood for your body

COVID-19 seems to be able to attack cells that line your blood vessels. Aside from heart issues, it can also cause blood clots that lead to a stroke or pulmonary embolism. People who are seriously ill with COVID-19 often have much more of a substance doctors call "D-dimer" in their blood. That signals more blood clots.

COVID-19 appears to cause problems with your nervous system as well, including seizures. They can be due to swelling in the brain or inflammation of your central nervous system. Other symptoms that could be linked to your brain include:

• Loss of consciousness
• Loss of sense of smell
• Stroke

Up to half of the people in the hospital for COVID-19 have enzyme levels in their blood that signal liver damage. It may not be the virus itself that causes it. Medication or an overworked immune system can cause this, too.

About a third of people in the hospital for COVID-19 get conjunctivitis, which you might know as pinkeye. It happens when a virus, bacteria, or allergen irritates the tissue that covers your eye and the inside of your eyelids.

This is common in people who are seriously ill from COVID. Medication, a misfiring immune system, low blood pressure, and conditions you had before you got the virus can all contribute to this.

Some studies show that up to 40% of people with COVID-19 are "asymptomatic." That means they don't feel sick or have symptoms. But the virus can still affect your body. X-rays and CT scans of some people without symptoms show lung damage including "ground-glass opacities," a typical lung lesion in people with COVID-19.