Keywords
There were 11,574 relevant publications with author keywords in the period from 1991 to 2020. To further identify the main research directions and core content in the field of coronavirus research, we classified the author keywords into six categories (Table 1). They were ”Epidemiological features”, ”Biological features”, ”Immune response features”, ”Age/sex”, ”Diseases/symptoms” and ”Diagnosis/therapy”. China, which was the origin of the outbreak, conducted numerous studies on the clinical characteristics and biochemical markers of COVID-19 and studied the routes of transmission, effective measures to control the spread of the disease (for instance, rapid outbreak responses and lockdowns), epidemiological characteristics, diagnostic methods, treatments (for instance, traditional Chinese medicine) and vaccines. As the COVID-19 epidemic spread worldwide, the areas of focus in various countries and territories ranged from epidemiological characteristics, prevention and control methods, aetiology and antibodies to disease transmission, detection, diagnosis, treatment and prognosis.