The article considers the features of the occurrence and course of secondary diseases of infectious and non-infectious genesis in patients with a diagnosis of COVID-19, and also examines individual clinical cases described in the literature. The author concludes that the results showed that major respiratory diseases, in particular COPD (chronical obstructive pulmonary disease) and smoking, are associated with severe COVID-19 outcomes. The results of this study can help policy makers, doctors and healthcare professionals in the front line to make evidence-based decisions and reduce the mortality and morbidity of this 21st century pandemic. Understanding the proportion of COVID-19 patients with acute respiratory bacterial co-infection and pathogens is critical for the treatment of COVID-19 patients and helps ensure responsible use of antibiotics and minimize the negative effects of overuse. In addition, this knowledge may have a significant impact on clarifying recommendations for empirical antibiotic therapy for patients with COVID-19.