COVID-19
NICE guideline [NG191] COVID-19 rapid guideline: managing COVID-19. Last updated: May 2025.
UK Health Security Agency Guidance COVID-19: epidemiology, virology and clinical features. Last updated: May 2022.
Virology
COVID is caused by the infection of the SARS-CoV-2 virus, an RNA virus that belongs to the coronavirus family.
Transmission
COVID-19 is mainly transmitted through infectious respiratory particles (droplets and aerosols)
- The SARS-CoV-2 virus-containing respiratory particles are released when someone with COVID-19 speaks / coughs / sneezes
- Another person can catch COVID-19 when these particles are inhaled or come into contact with the eye / nose / mouth
Indirect transmission can occur through contact with surfaces contaminated with the virus (fomite transmission).
Clinical Features
Patients present with varying severity of symptoms; 1 in 3 patients are asymptomatic.
Main symptoms of COVID-19:
- Fever
- New and continuous cough
- Loss of smell (anosmia)
- Loss of taste (ageusia)
Other symptoms include:
- Dyspnoea
- Fatigue
- Loss of appetite
- Myalgia
- Sore throat
- Headache
- Nasal congestion / runny nose
Severe Illness
NICE explicitly noted that the following suggests COVID-19 with the most severe illness:
- Severe shortness of breath at rest or difficulty breathing
- Reduced oxygen saturation levels measured by pulse oximetry
- Coughing up blood
- Blue lips or face
- Feeling cold and clammy with pale or mottled skin
- Collapse or fainting (syncope)
- New confusion
- Becoming difficult to rouse
- Reduced urine output
Investigation and Diagnosis
Recommended diagnostic samples for suspected cases:
| Upper respiratory tract sample (usually preferred) | ANY of the following:
|
| Lower respiratory tract sample | Sputum (if obtainable) |
Testing method:
- Lateral flow test – quick, less sensitive screening tool
- RT-PCR – diagnostic gold standard
Management
NICE recommends the following treatment for COVID-19
| Drug class | Drug | Indication / criteria |
|---|---|---|
| Antivirals | Nirmatrelvir plus ritonavir |
|
| Remdesivir |
|
|
| Molnupiravir |
|
|
| Corticosteroid | Dexamethasone / hydrocortisone / prednisolone |
DO NOT use if the patient does NOT require oxygen therapy |
| Immunomodulators | Tocilizumab (IL-6 inhibitor) |
|
| Baricitinib (JAK inhibitor) |
|
NICE explicitly mentioned NOT to use the following treatments for COVID-19
- Antibiotics (including azithromycin and doxycycline) – unless there is evidence of bacterial co-infection
- Colchicine
- Inhaled budesonide (only use as part of a clinical trial)
- Ivermectin (only use as part of a clinical trial)
- Vitamin D (only used as part of a clinical trial)