Overview
COVID-19 is an infectious respiratory illness caused by the SARS-CoV-2 coronavirus. It ranges from no symptoms at all to severe pneumonia requiring intensive care. Most people recover at home, but some develop prolonged symptoms lasting months (Long COVID).
How common is it?
COVID-19 infected hundreds of millions globally during the pandemic. It remains in circulation as an endemic respiratory virus that causes seasonal waves.
Causes and risk factors
The SARS-CoV-2 virus spreads mainly through respiratory droplets and aerosols from an infected person's breath, coughs, or sneezes. It enters cells via the ACE2 receptor found particularly in the lungs.
Common risk factors
- Close contact with infected person
- Unventilated indoor spaces
- Advanced age
- Obesity, diabetes, heart disease, or immunosuppression
- Not being vaccinated or boosted
- Certain occupations with high public contact
Symptoms
- Fever or chills
- New continuous cough
- Loss or change in sense of smell or taste
- Fatigue
- Shortness of breath
- Headache, sore throat, runny nose
- Muscle aches and pains
- Nausea or diarrhoea
When to see a doctor
Call 999 or go to A&E if you have severe breathlessness, persistent chest pain, confusion, difficulty staying awake, or lips or face turning blue. These indicate severe illness needing urgent care.
Diagnosis
Lateral flow antigen tests provide rapid home results. PCR tests are more sensitive. Blood tests, chest X-ray, and CT scans are used for hospitalised patients to assess severity.
Treatments
Supportive care at home
Rest, stay hydrated, and take paracetamol or ibuprofen for fever and pain. Most people with mild to moderate illness recover fully at home within 1 to 2 weeks.
Antiviral medication
Nirmatrelvir-ritonavir (Paxlovid) and other antivirals are offered to high-risk people early in illness to reduce hospitalisation risk. Must be started within 5 days of symptoms.
Hospital care for severe illness
Supplemental oxygen, dexamethasone, and other supportive measures. Intensive care with mechanical ventilation for the most severe respiratory failure.
Self-care and lifestyle
- Vaccination and boosters remain the most effective protection against severe disease
- Ventilate indoor spaces and use face coverings in crowded settings when transmission is high
- Long COVID symptoms should be discussed with a doctor for appropriate referral and support
- Pacing activity is important in Long COVID to avoid worsening fatigue
Prevention
Vaccination significantly reduces the risk of severe illness, hospitalisation, and death. Good ventilation, hand hygiene, and staying home when symptomatic reduce transmission.