1. the ability of a pathogen to establish an infection in a host
Usage: medical; scientific
2. the degree to which something is infectious or capable of spreading disease
Usage: medical; scientific

Examples

• The virus showed high infectivity in laboratory tests.
• Researchers measured the infectivity of different bacterial strains.
• Hand washing reduces the infectivity of many common pathogens.
• The infectivity of the disease decreased after vaccination programs began.
• Scientists study infectivity to understand how diseases spread.
• Temperature and humidity can affect the infectivity of airborne viruses.