Respiratory system
Pandemic
Virology
Respiratory tract infections
Respiratory tract
Virus
Coronavirus disease 2019 (COVID-19)
Lower respiratory tract infection
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
Pneumonia
Medicine
Influenza A virus
2019-20 coronavirus outbreak
Immunology
Biology
Internal medicine
Disease
Infectious disease (medical specialty)
Outbreak
