COVID-19 is caused by the SARS-CoV-2 virus. It can range from a mild illness to a serious condition, and some people develop lasting symptoms. Vaccines and treatments now exist; the early-pandemic information previously on this page is no longer an appropriate guide.
Seek emergency help for difficulty breathing, persistent chest pain or pressure, new confusion, inability to wake or stay awake, or pale, grey or blue lips or skin. Call your local emergency number and explain that COVID-19 may be involved.
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Symptoms do not give a certain diagnosis
Possible symptoms include fever, cough, sore throat, congestion, fatigue, headache, body aches, changes in smell or taste, and digestive symptoms. Some people have few symptoms. Flu and COVID-19 overlap, so symptoms alone cannot reliably tell them apart.
Follow current local testing advice and the instructions supplied with your test. If you are at higher risk of serious illness, contact a clinician promptly rather than waiting for symptoms to become severe.
Early treatment can matter
Antiviral treatment may reduce the risk of hospitalization or death in eligible people. CDC advises that treatments must begin within five to seven days of symptom onset, depending on the medicine. Ask about eligibility as soon as you become ill.
Older age, a weakened immune system and certain medical conditions can increase risk. A clinician or pharmacist must check suitability, other medicines and possible interactions. Do not use someone else’s prescription or an unapproved product advertised as a cure.
Before contacting care, note when symptoms began, your test results if available, your medical conditions and all medicines or supplements you take. Having that information ready can help a time-sensitive consultation.
How it spreads
An infected person releases virus-containing droplets and small particles when breathing out. Others can breathe these in or receive particles on their eyes, nose or mouth. People can spread infection without symptoms. Cleaning surfaces alone is therefore not a complete prevention plan.
Reduce risk for yourself and others
- Cleaner air: improve ventilation and use appropriate air-cleaning measures where practical.
- Illness precautions: stay away from others when sick and follow current local guidance about returning to usual activities.
- Masks and distance: these can add protection, especially around people at higher risk.
- Vaccination: discuss the current recommendation for your age, health and location with a healthcare professional.
- Hygiene: keep up regular handwashing and respiratory hygiene.
Vaccine schedules, eligibility and workplace or healthcare-setting rules can change. Use the linked official guidance and your local health authority for current details instead of relying on a fixed schedule in an old article.
Persistent symptoms deserve care
Long COVID can involve ongoing or recurring symptoms after infection, including after an initially mild illness. It can affect daily life and sometimes cause disability. There is no single approved laboratory test that determines whether symptoms are due to Long COVID.
If symptoms persist, discuss them with a clinician and explain how they affect activities, sleep or work. A personal management plan and assessment for other causes can be useful; do not dismiss symptoms because an initial test is normal.
Sources
- CDC: COVID-19 and transmission
- CDC: symptoms and emergency signs
- CDC: treatment options
- CDC: prevention
- CDC: Long COVID
Editorial update: October 1, 2026. Replaced the 2020 article’s outdated statistics, vaccine claims and prevention advice. This is general information, not individual medical advice. Consult current local guidance. Send corrections through our Contact Us page.
