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(Lee 2020). Of 63 asymptomatic patients in Chongquing, 9 (14%) transmitted the virus to others (Wang Y 2020). Taken together, these preliminary studies indicate that a significant proportion (20-60%) of all COVID-19 infected subjects may remain asymptomatic during their infection. The studies show a broad range, depending on the populations and probably on methodological issues. It will be very difficult (if not impossible) to clarify the exact proportion.
Symptoms A plethora of symptoms have been described in the past months, clearly indicating that COVID-19 is a complex disease, which in no way consists only of a respiratory infection. Many symptoms are unspecific so that the differential diagnosis encompasses a wide range of infections, respiratory and other diseases. However, different clusters can be distinguished in COVID-19. The most common symptom cluster encompasses the respiratory system: cough, sputum, shortness of breath, and fever. Other clusters encompass musculoskeletal symptoms (myalgia, joint pain, headache, and fatigue), enteric symptoms (abdominal pain, vomiting, and diarrhea); and less commonly, a mucocutaneous cluster. An excellent review on these extrapulmonary organ-specific pathophysiology, presentations and management considerations for patients with COVID-19 was recently published (Gupta 2020).
Fever, cough, shortness of breath Symptoms occur in the majority of cases (for asymptomatic patients, see below). In early studies from China (Guan 2020, Zhou 2020), fever was the most common symptom, with a median maximum of 38.3 C; only a few had a temperature of > 39 C. The absence of fever seems to be somewhat more frequent than in SARS or MERS; fever alone may therefore not be sufficient to detect cases in public surveillance. The second most common symptom was cough, occurring in about two thirds of all patients. Among survivors of severe COVID-19 (Zhou 2020), median duration of fever was 12.0 days (8-13 days) and cough persisted for 19 days (IQR 12-23 days). According to a systemic review, including 148 articles comprising 24,410 adults with confirmed COVID-19 from 9 countries (Grant 2020), the most prevalent symptoms were fever (78%), cough (57%) and fatigue (31%). Fever and cough do not distinguish between mild and severe cases nor do they predict the course of COVID-19 (Richardson 2020, Petrilli 2020). In contrast, shortness of breath has been identified as a strong predictor of severe disease in larger studies. In a cohort of 1,590 patients, dyspnea was associated
Kamps – Hoffmann
