COVID-19 / Wuhan novel coronavirus

COVID-19 / Wuhan Novel Coronavirus

On 31 December 2019, the World Health Organization (WHO) was informed of a cluster of cases of respiratory illnesses of unknown cause in Wuhan City, China. On 11 March 2020, the WHO then announced a COVID-19 global pandemic was occurring due to the rapid spread and severity of cases worldwide.

Coronaviruses (CoVs) primarily cause enzootic infections in birds and mammals but, in the last few decades, have shown to be capable of infecting humans as well

• the outbreak of severe acute respiratory syndrome (SARS) in 2003 and, more recently, Middle-East respiratory syndrome (MERS) demonstrated the lethality of CoVs when they cross the species barrier and infect humans
• the outbreak of COVID-19 is another example of coronavirus infecting humans (1)

Severe acute respiratory illness with fever and respiratory symptoms, such as cough and shortness of breath, comprise the working case definition used to select people for viral testing

Fever, cough or chest tightness, myalgia, fatigue and dyspnoea are the main symptoms reported.

A variety of abnormalities may be expected on chest radiographs, but bilateral lung infiltrates appear to be common (similar to what is seen with other types of viral pneumonia).

The majority of patients have mild illness that does not warrant medical intervention or hospitalisation, depending on the circulating SARS-CoV-2 variant.

Common symptoms include: (2,3)

• fever
• cough
• fatigue
• myalgia
• arthralgia
• dyspnoea
• altered sense of taste/smell
• sore throat
• headache
• rhinorrhoea
• nasal congestion
• sneezing
• expectoration.

One Cochrane review found that the presence of anosmia and/or ageusia may be useful as a red flag for diagnosis. Cough or fever may also increase the probability of diagnosis to an extent that is clinically relevant and should prompt further testing. (4)

Note - no single sign or symptom can accurately diagnose COVID-19, and neither the absence or presence of specific signs or symptoms are accurate enough to rule in or rule out disease.

Other possible symptoms include;

• gastrointestinal symptoms such as diarrhoea can be the initial manifestation of infection
  
• neurological symptoms, including ischaemic or haemorrhagic stroke, dizziness, headache, musculoskeletal disturbance, altered mental state, Guillain-Barré syndrome, and acute necrotising encephalopathy
  
• cardiovascular events such as myocardial injury, venous and arterial thromboembolic disease
  
• ocular manifestations - such as conjunctival hyperaemia, chemosis, and increased secretions

The National Institute for Health and Care Excellence gives the following definitions: (2)

Acute COVID-19 - defined as signs and symptoms of infection consistent with COVID-19 for up to 4 weeks.

Ongoing symptomatic COVID-19 - defined as signs and symptoms of COVID-19 infection from 4 weeks up to 12 weeks.

Post-COVID-19 syndrome - defined as signs and symptoms that develop during or after an infection consistent with COVID-19, continue for more than 12 weeks, and are not explained by an alternative diagnosis. Typically presents with clusters of symptoms which may overlap, fluctuate, and change over time, affecting any body system.

'Long COVID' - defined as signs and symptoms that develop during or after an infection consistent with COVID-19, continue for more than 4 weeks, and are not explained by an alternative diagnosis. This now includes both 'ongoing symptomatic COVID-19' and 'post-COVID-19 syndrome'

References

1. Coronaviridae Study Group of the International Committee on Taxonomy of Viruses. The species severe acute respiratory syndrome-related coronavirus: classifying 2019-nCoV and naming it SARS-CoV-2. Nat Microbiol. 2020 Apr;5(4):536-44.
2. NICE. COVID-19 rapid guideline: managing COVID-19. NICE guideline NG191. Published March 2021, last updated May 2025.
3. Luo X, Lv M, Zhang X, et al. Clinical manifestations of COVID-19: an overview of 102 systematic reviews with evidence mapping. J Evid Based Med. 2022 Sep;15(3):201-15.
4. Struyf T, Deeks JJ, Dinnes J, et al. Signs and symptoms to determine if a patient presenting in primary care or hospital outpatient settings has COVID-19. Cochrane Database Syst Rev. 2022 May 20;5(5):CD013665.