History and exam

Key diagnostic factors

Reported in 83% to 98% of patients in case series.[20][21][37][109][110][136] In one case series, 44% of patients had a fever on presentation, but it developed in 89% of patients after hospitalisation.[108]

Children may not present with fever, or may have a brief and rapidly resolving fever.[12][115][116]

Patients may present with chills/rigors.

The course of fever is not fully understood yet, but it may be prolonged and intermittent.

Reported in 57% to 82% of patients in case series.[20][21][37][108][109][110][136]

Less common in children.[115]

Cough is usually dry.

Reported in 18% to 55% of patients in case series.[20][21][37][108][110][136]

Median time from onset of symptoms to development of dyspnoea is 5 to 8 days.[20][21][37]

Polypnoea has been reported in children with severe illness.[118]

Other diagnostic factors

Reported in 29% to 69% of patients in case series.[20][37][108][110][136]

Patients may also report malaise.

Reported in 11% to 44% of patients in case series.[20][21][37][108][109][136]

Reported in 40% of patients in case series.[37]

Reported in 26% to 33% of patients in case series.[20][37][108][136]

Reported in 5% to 17% of patients in case series, and usually presents early in the clinical course.[21][37][108][136]

Children may have pharyngeal erythema.[115]

Reported in 9% of patients in case series.[21]

Reported in 9% to 12% of patients in case series.[37][110]

Reported in 6% to 14% of patients in case series.[20][21][37][108][110][136]

Nausea, vomiting, abdominal pain, and diarrhoea have been reported in 1% to 11% of patients in case series, although this may be underestimated.[20][21][37][108][110][136][137] One case series reported gastrointestinal symptoms in nearly 40% of patients.[138]

Some patients may present with predominantly gastrointestinal symptoms, especially children.[119][120][139]

Patients may present with nausea or diarrhoea 1 to 2 days prior to onset of fever and breathing difficulties.[37]

Reported in 1% to 5% of patients in case series.[20][108]

Reported in 4% to 5% of patients in case series.[21][108]

Reported in 2% to 5% of patients in case series.[20][21]

May indicate pneumonia.

Reported in <1% of patients in case series.[108]

There is anecdotal evidence that patients with mild illness may develop anosmia/hyposmia or ageusia/dysgeusia as an early symptom and in the absence of other symptoms. In one small cross-sectional survey in Italy, approximately 53% of hospitalised patients reported at least one taste or olfactory disorder (or both).[140] It is possible that these patients may be hidden carriers, but further research is required.[141]

The American Academy of Otolaryngology - Head and Neck Surgery has proposed adding anosmia and dysgeusia to the list of screening items for potential infection and recommends that clinicians consider testing and self-isolation of these patients (in the absence of other respiratory diseases such as rhinosinusitis or allergic rhinitis).[142]

Cutaneous manifestations (e.g., erythematous rash, petechiae, urticaria, vesicles) have been reported in some patients; however, further data is required to better understand skin involvement.[143][144]

May indicate pneumonia.

May be present in patients with acute respiratory distress.

May be present in patients with acute respiratory distress.

May be present in patients with acute respiratory distress.

May be present in patients with acute respiratory distress.

Risk factors

Diagnosis should be suspected in patients with acute respiratory illness (i.e., fever and at least one sign/symptom of respiratory disease such as cough or shortness of breath) and a history of travel to or residence in a location reporting community transmission of COVID-19 disease during the 14 days prior to symptom onset.[75]

WHO: novel coronavirus (COVID-19) situation dashboard external link opens in a new window

CDC: locations with confirmed COVID-19 cases, by WHO region external link opens in a new window

Diagnosis should be suspected in patients with any acute respiratory illness if they have been in contact with a confirmed or probable COVID-19 case in the last 14 days prior to symptom onset.[75]

People aged 65 years and older, those who live in a nursing home or long-term care facility, and those with a high-risk condition (e.g., chronic respiratory disease, cardiovascular disease, immunocompromised, severe obesity, diabetes, hypertension, renal or liver disease) are at higher risk for severe illness.[76]

The most prevalent comorbidities in patients with COVID-19 are hypertension, diabetes, cardiovascular disease, and respiratory disease.[77]

Initial data suggest that immunosuppressed patients are not at increased risk of severe illness from coronaviruses; however, further research is required on this patient group.[78]

Patients with cancer are thought to be at a higher risk of contracting COVID-19 because treatments such as radiotherapy and chemotherapy are immunosuppressive, and patients with cancer are often in hospital for treatment and monitoring and so may be at risk of nosocomial infection. A retrospective study of 1524 patients at a single institution in Wuhan City, China, found that the infection rate in patients with cancer was higher than the cumulative incidence of all diagnosed cases reported in the city over the same period of time (i.e., 0.79% versus 0.37%). However, fewer than half of these infected patients were undergoing active treatment, suggesting that recurrent hospital visits and admissions were a potential risk factor.[79]

Early data on smoking as a risk factor for severe illness appear to be conflicting. Preliminary results from a meta-analysis found that active smoking is not significantly associated with an increased risk of severe disease.[80] However, a systematic review found that smoking is likely associated with negative progression and adverse outcomes.[81] Further research is warranted.

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