Overview
COVID-19 is an infectious disease caused by the SARS-CoV-2 virus. It mainly affects the respiratory system, but it can also affect other parts of the body. Some people recover within days to weeks, while others become seriously ill or have symptoms that last longer.
Key Symptoms
Common symptoms include fever, cough, sore throat, runny nose, fatigue, headache, muscle aches, and loss of taste or smell. Some people have shortness of breath, nausea, vomiting, or diarrhea. Symptoms may begin a few days after exposure, and some infected people have no symptoms but can still spread the virus.
Causes and Risk Factors
COVID-19 happens when a person is infected with the SARS-CoV-2 virus. The virus spreads most often through the air when an infected person breathes, talks, coughs, or sneezes, especially indoors with poor ventilation or close contact. The risk of severe illness is higher in older adults and in people with certain medical conditions or weakened immune systems.
Who Is Affected
Anyone can get COVID-19, including children and adults. People living in crowded settings, those with frequent close contact with others, and people without access to vaccination or healthcare may face higher exposure risks. Severe outcomes are more common in older adults, pregnant people, and people with chronic health conditions.
Prevention
Prevention can include staying up to date with COVID-19 vaccination, improving indoor ventilation, avoiding close contact with people who are sick, and wearing a well-fitting mask in higher-risk situations. Hand hygiene and covering coughs and sneezes also help reduce spread. If you are sick, staying home and away from others can help protect people around you.
Diagnosis and Tests
COVID-19 is usually diagnosed with a viral test, such as a rapid antigen test or a laboratory-based molecular test. Testing may be helpful if you have symptoms, were exposed, or need to make decisions about work, school, travel, or visiting others at higher risk. A healthcare professional may also consider your symptoms, exposure history, and overall health.
Treatment Categories
Treatment depends on how sick a person is and whether they are at higher risk for severe illness. Care may include rest, fluids, symptom relief, monitoring, and medical evaluation for breathing problems or other complications. Some people may be eligible for antiviral treatment, and severe cases may require hospital care.
Living With It
Most people recover at home, but recovery time varies. It can help to rest, drink fluids, monitor symptoms, and follow local public health guidance about reducing spread to others. Some people develop longer-lasting symptoms after the initial infection and may need follow-up medical care.
When to Seek Medical Care
Seek medical care if symptoms are getting worse, if you are at higher risk for severe illness, or if you are unsure whether you need testing or treatment. Contact a healthcare professional promptly if you have breathing trouble, chest discomfort, dehydration, or symptoms that are not improving. Early medical advice can be especially important for people with chronic conditions, pregnancy, or weakened immune systems.
When It May Be an Emergency
Get emergency help right away if someone has severe trouble breathing, persistent chest pain or pressure, new confusion, trouble staying awake, or blue, gray, or pale lips, skin, or nails depending on skin tone. Emergency signs can be different in children, older adults, and people with disabilities. If you think it is an emergency, contact local emergency services immediately.