- Coronaviruses cause respiratory illnesses, so the lungs are usually affected first.
- Early symptomsTrusted Source include fever, cough, and shortness of breath. These appear as soon as 2 days, or as long as 14 days, after exposure to the virus.
- But damage can also occur in other parts of the body, especially during serious illness.
All data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our coronavirus hub and follow our live updates page for the most recent information on the COVID-19 outbreak.
There’s still a lot we don’t know about the new coronavirus that’s sickened more than 3.2 million worldwide, with more than 230,000 deaths reported.
But one thing that’s clear is that in serious cases, the virus can have a devastating effect on the body — and not just on the lungs.
Here’s what we know so far about how COVID-19, the disease the new coronavirus causes, affects the different systems in the body.
COVID-19 affects lungs
As with other coronavirusTrusted Source illnesses — including SARS, MERS, and the common cold — COVID-19 is a respiratory disease, so the lungs are usually affected first.
Early symptomsTrusted Source include fever, cough, and shortness of breath. These appear as soon as 2 days, or as long as 14 days, after exposure to the virus.
While fever is at the top of the Centers for Disease Control and Prevention’s list of symptoms, not everyone who gets sick has a fever. In one study in the Journal of the American Medical Association, researchers found that around 70 percentTrusted Source of patients hospitalized with COVID-19 didn’t have a fever.
Cough is more common, but treatment guidelines developed by Boston’s Brigham and Women’s Hospital found that cough occurs in 68 to 83 percent of people who show up at the hospital with COVID-19.
Only 11 to 40 percent had shortness of breath.
Other less common symptoms included confusion, headache, nausea, and diarrhea.
The severity of COVID-19 varies from mild or no symptoms to severe or sometimes fatal illness. Data on more than 17,000 reported cases in China found that almost 81 percent of cases were mild. The rest were severe or critical.
Older people and those with chronic medical conditions appear to have a higher riskTrusted Source for developing severe illness.
This variability also shows up in how COVID-19 affects the lungs.
Some people may only have minor respiratory symptomsTrusted Source, while others develop non-life-threatening pneumonia. But there’s a subset of people who develop severe lung damage.
“What we’re frequently seeing in patients who are severely ill with [COVID-19] is a condition that we call acute respiratory distress syndrome, or ARDS,” said Dr. Laura E. Evans, a member of the Society of Critical Care Medicine Leadership Council and an associate professor of pulmonary, critical care, and sleep medicine at the University of Washington Medical Center in Seattle.
ARDS doesn’t happen just with COVID-19. A number of events can trigger it, including infection, trauma, and sepsis.
These cause damage to the lungs, which leads to fluid leaking from small blood vessels in the lungs. The fluid collects in the lungs’ air sacs, or alveoli. This makes it difficult for the lungs to transfer oxygen from the air to the blood.
While there’s a shortage of information on the type of damage that occurs in the lungs during COVID-19, a recent report suggests it’s similarTrusted Source to the damage caused by SARS and MERS.
One recent studyTrusted Source of 138 people hospitalized for COVID-19 found that on average, people started having difficulty breathing 5 days after showing symptoms. ARDS developed on average 8 days after symptoms.
Treatment for ARDS involves supplemental oxygen and mechanical ventilation, with the goal of getting more oxygen into the blood.
“There isn’t a specific treatment for ARDS,” Evans said. “We just support the person through this process as best we can, allowing their bodies to heal and their immune system to address the underlying events.”
One curious thing about COVID-19 is that many patients have potentially deadly low blood oxygen levels, but they don’t seem starved of oxygen. This has led some doctors to rethink putting patients on a ventilator simply because of low oxygen levels in the blood.