Yes, infectivity can change over time due to several factors:
1. Mutations: Pathogens can mutate, potentially altering their infectivity. For instance, new variants of viruses may spread more easily. 2. Population Immunity: As more individuals become immune, either through infection or vaccination, the effective reproduction number (Re) decreases. 3. Interventions: Public health measures like social distancing, vaccination, and improved hygiene can reduce the infectivity of a pathogen.
