What Is COVID-19?
COVID-19, short for COronaVIrus Disease 2019, is a respiratory illness caused by a novel coronavirus first detected in China in late 2019. Early transmission of the coronavirus was linked to an animal market, suggesting animal-to-person infection. By January 2020, with the spread of coronavirus disease to over 100 other locations, including the U.S., the World Health Organization (WHO) officially declared the outbreak a public health emergency and later, a pandemic. Only months later, confirmed cases of COVID-19 were recorded in almost every country around the world.
How It Affects Your Body
The lungs are the first body organ affected by COVID-19. In the early days of an infection, the novel coronavirus rapidly invades cells in our respiratory system. COVID-19 is thought to attack the epithelial cells lining the airways—that catch and clear out things like pollen and viruses—flooding our airways with debris and fluids.
People who become sick with COVID-19 may experience mild to severe disease, or in many cases be asymptomatic (have no symptoms). COVID-19 symptoms, such as cough and shortness of breath, can come on suddenly. Severe illness may cause a number of complications that require medical intervention, including:
- Acute respiratory distress syndrome
- Cardiac disease
- Blood clots
- Kidney disease
- Organ failure
COVID-19 can be fatal for anyone, though the greatest percentage of individuals who die are over the age of 85 or are living with a chronic disease.
Some individuals, even those with mild illness that did not require hospitalization, experience prolonged or new symptoms post-infection. Learn more about post-COVID long term symptoms.
Watch this video from The New York Times that shows how coronavirus attacks the body.
People at Higher Risk for Severe Illness
The novel coronavirus has never before been seen in humans so we have no immunity to it and everyone is at risk of becoming infected with the virus that causes COVID-19. Some individuals, such as healthcare professionals and those caring for people sick with COVID-19, are more likely to get infected than others.
Anyone can have mild to severe symptoms from COVID-19, and some people are asymptomatic (have no symptoms). There are some individuals who are at higher risk for severe illness. Based on current information:
- Risk increases as you age so the older you are, the higher your risk with the greatest threat being to individuals over the age of 85 years old
- People of all ages with underlying medical conditions, particularly if not well controlled, including:
- People with chronic obstructive pulmonary disease (COPD).
- People who are immunocompromised from solid organ transplantation.
- People living with a current cancer diagnosis
- People who are a current or former smoker
- People with obesity (body mass index [BMI] of 30 or higher) and especially severe obesity (BMI of 40 or higher)
- Other medical conditions including serious heart conditions, type 2 diabetes, sickle cell disease, pregnancy, Down Syndrome, and people with chronic kidney disease.
As of December 23, 2020, the CDC lists people with chronic health conditions that might be at an increased risk of severe illness. Some of the listed conditions include: moderate-to-severe asthma, pulmonary fibrosis, cystic fibrosis, hypertension, liver disease, type 1 diabetes mellitus, neurological conditions such as dementia, cerebrovascular disease, being overweight (BMI of 25 or higher),or being in an immunocompromised state from use of corticosteroids or other immune weakening medicines.
Children have been less affected by COVID-19 than adults, though they can also experience severe symptoms. Similar to adults, children with underlying medical conditions might place them at increased risk, including asthma and other chronic lung diseases, obesity, medical complexity, severe genetic disorders, sickle cell disease, congenital heart disease, diabetes, chronic kidney disease, and immunosuppression due to cancer or immune-weakening medications. Infants under one year of age might also be at increased risk of severe illness.
Reviewed and approved by the American Lung Association Scientific and Medical Editorial Review Panel.
Page last updated: January 29, 2021