People with COVID-19 are most contagious around day four of symptoms, with contagiousness peaking when symptoms peak, which is several days into the illness. They can be contagious starting up to 2-3 days before symptoms appear and remain contagious for an average of about eight days. The contagious period may vary based on the severity of illness and individual health conditions. Even after symptoms improve, precautions should be taken for an additional five days. This pattern, influenced by immunity from vaccination and prior infection, resembles that of flu and similar respiratory viruses.
In summary:
- Contagious starting 2-3 days before symptoms.
- Most contagious around day four after symptoms begin.
- Contagious for an average of 8 days total.
- Contagiousness decreases after symptom peak but persists.
- Precautions recommended for several days after symptoms improve.
