The common cold, the flu, and COVID-19 are all caused by respiratory viruses and share some of the same symptoms, but they can cause very different outcomes.

The common cold can be caused by a variety of viruses, including adenoviruses and coronaviruses. Typical symptoms include nasal congestion (stuffy or runny nose), sneezing, sore throat, and cough; fever is rare. Nasal secretions and phlegm can be thick and white, yellow or greenish.

The flu can also cause these symptoms, but more often it manifests as fever or chills, fatigue, headache, and muscle or joint pain. Some people, especially children, may experience gastrointestinal symptoms, such as nausea or diarrhea. Flu symptoms tend to come on more suddenly and are usually more severe than cold symptoms.

Common symptoms of COVID-19, caused by a novel coronavirus named SARS-CoV-2, include fever or chills, dry cough and shortness of breath. But COVID-19 can also be marked by a wide range of other symptoms. One of the most distinctive signs of COVID-19 is loss of sense of taste or smell. Many people have no symptoms.

Colds usually resolve in about a week without treatment. Most people with the flu or COVID-19 recover within weeks, but these illnesses are more likely to cause serious complications. Older people are more likely to have severe flu or COVID-19; young children are more likely to have severe influenza, but are at low risk for severe COVID-19.

People with mild illness can usually manage their symptoms at home with supportive care, including drinking plenty of fluids, getting enough rest, and taking over-the-counter medications. These viral diseases cannot be treated with antibiotics. Consult a doctor if you or your child develop a high fever, have difficulty breathing or suffer from mental confusion.

If you have any of these symptoms, stay home, avoid close contact with other people, cover coughs and sneezes, and take other recommended precautions. You can visit your nearest hospital or book home sample collection. The Covid-19 test is the only way to know for sure if you have a cold, the flu or SARS-CoV-2. Getting the flu shot is more important than ever during the COVID-19 pandemic.