Most people with COVID have mild or moderate illness and will recover without special treatment. Some have few or no symptoms, but they can still transmit the virus to others. In some cases, however, SARS-CoV-2 causes severe respiratory problems and can lead to hospitalization and death. People over 65, immunocompromised people and those with comorbidities are more likely to develop severe illness.

The most common early symptoms of COVID-19 are cough, shortness of breath, fever or chills, fatigue, muscle or body aches and headache. Some people develop gastrointestinal symptoms, such as nausea or diarrhea. Loss of the sense of taste or smell is a distinctive COVID symptom.

Symptoms vary somewhat for the different SARS-CoV-2 variants, and the currently circulating omicron variants appear to cause milder illness. It takes around five days, on average, between exposure to the virus and the appearance of symptoms.

As the disease progresses, people may find it increasingly difficult to breathe. In serious cases, they may develop pneumonia, in which air sacs in the lungs fill with fluid, preventing oxygen from entering the bloodstream. In the most severe cases, patients can develop acute respiratory distress syndrome, or widespread lung inflammation that requires oxygen therapy or mechanical ventilation.

COVID can also affect other organs throughout the body, including the cardiovascular system and brain. Some people with SARS-CoV-2 develop prolonged symptoms, known as long COVID, that can last for months or years.

Last Reviewed: September 15, 2023