Symptoms and complications
Symptoms and complications
Covid-19 infects the upper and lower respiratory tracts and is mainly spread by aerosol droplets released by an infected person, while sneezing and coughing. These droplets can be inhaled by other people. Some transmission occurs by transfer of the virus from contaminated hard surfaces or contact with the skin of infected people. The virus can survive on hard surfaces for up to 72 hours, and for several hours on the skin (longer than the cold or flu virus).
Since the emergence of SARS-CoV-2, a number of different variants have been identified with differences in their transmissibility and in virulence. The most common symptoms attributed to the alpha variant in the ‘first wave’ of the pandemic were fever, a new and continuous cough, shortness of breath, fatigue, loss of appetite, anosmia (loss of smell) and ageusia (loss of taste). In some people, taste is changed or disturbed (dysgeusia).
Other symptoms seen with most variants include headache, muscle pain, sore throat, nasal congestion, chest pain, nausea and vomiting, diarrhoea and skin rashes (especially in younger people). The illness is variable in severity, from asymptomatic, to mild respiratory infection in some people, to severe pneumonia in others. Delirium and reduced mobility can occur in the elderly and immunocompromised people, often in the absence of fever.
Studies of the omicron variant – the predominant variant in the UK at the time of writing – show that the most common symptoms are like those of the common cold, with headache, runny nose and sore throat.
Red flags for urgent care of Covid-19
- Severe shortness of breath at rest or difficulty breathing
- Reduced oxygen saturation levels measured using pulse oximetry
- Oxygen saturation levels below 91 per cent in room air at rest in children and young people (17 years and under) with Covid-19, or below 92 per cent in people aged 18 years and over
- 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.
Prolonged symptoms and long-Covid
The number of people affected by prolonged symptoms and long-Covid is considerable and a major concern. In most people the symptoms of Covid-19 resolve completely within four weeks of infection but a sizeable minority (estimated 10-20 per cent) continue to have symptoms beyond four weeks and are said to have long-Covid.
The National Institute for Health and Care Excellence (NICE) defines ‘post-Covid-19 syndrome’ as when signs continue for more than 12 weeks and are not attributable to alternative diagnoses. There does seem to be some evidence that long-Covid is seen less with the omicron variants.
Thankfully most people have a mild infection which can be treated at home. Patients should be advised to rest and avoid strenuous activity, and to drink fluids regularly to avoid dehydration. Fluid intake needs may be higher than usual in cases of fever. Paracetamol or ibuprofen may help with symptom relief.
NICE advise that people with cough should avoid lying on their backs, if possible, because this may make coughing less effective at clearing mucus. If people are unable to self-care, have severe symptoms, or are immunosuppressed, the advice is to contact the NHS 111 online for telephone assessment. See boxout for an outline of ‘red flags’ requiring urgent review.