People with COVID-19 are contagious from about 48 hours (2 days) before symptoms appear or even before testing positive if asymptomatic, and remain contagious typically for up to 10 days after symptoms begin. Some individuals, especially those who are severely ill or immunocompromised, may be contagious for longer—up to 20 days. The highest contagiousness is usually in the 1-2 days before symptoms start and during the first 5 days of symptoms. Even without symptoms, a person can spread the virus during the incubation period, which averages about 5 days but can range from 2 to 14 days depending on the variant.
Key points on contagiousness:
- Contagious starting 48 hours before symptoms or positive test if asymptomatic.
- Most contagious 1-2 days before symptoms and in first 5 days of illness.
- Typical contagious period lasts up to 10 days.
- Longer contagious period (up to 20 days) possible for severe cases or weakened immune systems.
- Virus spreads through respiratory droplets and particles when talking, coughing, sneezing, or breathing.
- Asymptomatic people can still spread the virus during the incubation period (2 to 14 days).
Variant note:
- Omicron variant has a shorter incubation period (about 3-4 days) and can spread faster.
- The general contagious timeline remains similar but may vary with different variants.
Thus, isolation or precautions like mask-wearing are important during this contagious period to reduce transmission risk.
