Microbiology is the study of all living organisms that are too small to be visible with the naked eye. This includes bacteria, archaea, viruses, fungi, prions, protozoa and algae, collectively known as 'microbes' (definition by Microbiology Society). Microbiologists study cell biology, ecology, evolution, and clinical aspects of microorganisms, including host responses to microbes. Virology is a subfield of Microbiology that focuses on viruses and virus-like organisms (viroids, prions, etc.). At Georgia State, researchers study bacteria as pathogens, as members of a community of microbes (microbiota) necessary for the health of host organisms and the environment, and as agents in biomanufacturing. A relatively large number of Georgia State researchers study the detection, nature, and control of virus-borne diseases, such as COVID-19, Ebola, and HIV.

Wikipedia description of Microbiology
Wikipedia description of Virology