Contagiousness varies from virus to virus. For example, most of the patients with flu are contagious only after they develop symptoms, while people with Covid can be contagious 2 to 3 days before they develop symptoms or even if they do not develop any symptoms.
The duration of contagiousness also varies from virus to virus. People were contagious for a period of 10 to 14 days with the original strain of Covid; however, people with Delta variant appear to be contagious for longer periods of 3 to 4 weeks.
admin Answered question August 27, 2021