BINOMIAL NOMENCLATURE is a method of naming and classification used for naming and classifying living organism in their respective taxa in accordance with their characteristics.
CARLOUS LINEOUS was the scientist who developed this system.
It is confusing to use common names because common names have no scientific basis and are of no use while naming organism also many organisms may have different common names in different areas of world.
Scientists use Latin or Greek language for naming and classification.
The first name in a scientific name is the genus name.
The second name in a scientific name is the specie name.
Because you body is introduced to the virus, it is familiar to it and can build up an immunity to the weakened form so when the actual virus invades, your body know what to do.