This article presents a review of the literature and data from a personal study concerning the clinical manifestations of new coronavirus infection in patients hospitalized during the COVID-19 epidemic depending on their age. It was found that most patients complained about dry or low-productive cough, moderate general weakness. The patients aged 18–30 years old more frequently experienced no cough. The patients aged 31–40 years old significantly more frequently complained about dry cough (p < 0.05). Low-productive cough was less frequent but typical in all age groups and more frequent in patients aged 51–60 years. Moist cough was more frequent in patients over 60 years. Chest pain was registered in patients over 60 years (p < 0.05). The frequency of dyspnea was found to increase with age. More often dyspnea was registered in patients older than 60 years old. No dyspnea was noted in young patients aged 18–30 years. Half of the patients aged 18–30 years had no fever. At hospitalization, the average temperature was within normal or subfebrile, which predominated in patients aged 41–50 years (p < 0.05). The frequency of febrile fever increased in patients with age. There was no significant difference in the frequency of pyretic temperature among all age groups. The patients aged over 30 years complained more about moderate weakness, and patients aged over 40 years complained more about severe weakness. Younger patients more often complained about a sore throat, while older patients had practically no symptoms (p > 0.05). Thoracic pain was significantly more frequently registered in patients older than 60 years old. Young patients aged 18–30 years and 31–40 years had no chest pain.

The article presents a review of the literature sources and results of a personal study. It was found that in our group, there were more persons aged 18–30 years among those who were in inpatient treatment, and among those who were treated in the ICU, the patients were aged 60 years or over. On average, patients who were treated in the ICU were admitted on the 6th day of illness. Most patients complained of dry or unproductive cough, moderate general weakness. Relatively more often moderate general weakness was registered in patients with a moderate course, and moderate and pronounced was typical for patients with a severe course (p < 0.05). Dyspnea was predominantly found in severely ill patients (in one-third of patients during exercise, in 17.7 % patients at rest). In patients with a non-serious course, a small number of patients had dyspnea on exertion (4.3 to 12.1 %). On admission, the average temperature was within normal or subfebrile, which predominated in patients with a moderate course (p < 0.05). With a mild course, half of the patients had a temperature within the normal range. Febrile fever was more often registered in the moderate and severe course. Pyretic body temperature was most typical for a severe course (p < 0.05). It is noteworthy that even in those patients who were treated in the intensive care unit, at admission a quarter of the patients had a normal temperature, and 41.2 % — subfebrile. On ave-rage, the duration of fever before admission in critically ill patients was 5 days, and in those who died — 2 days. Dry cough was significantly more common in severe patients (p < 0.05). In the mild course, only one-fifth of patients complained of dry or unproductive cough. In the moderate course, the dry or unproductive cough was symptomatic for one-third of patients. There was no significant difference in the frequency of complaints of sore throat (p > 0.05). On average, a respiratory rate on admission in critically ill patients did not differ between those who survived and those who died, while those who died more often presented with a respiratory rate of 30/min or more, tachycardia, and more reduced saturation values.