How long is a cold contagious?

Usually from about a day before symptoms until 5–7 days after onset, with peak spread in the first 2–3 days. Children may shed longer. Hand hygiene and staying home during the worst days do more than masks alone.

Peak shedding is in the first 2-3 days, which is when staying home makes the biggest difference.

Hand hygiene matters because rhinovirus spreads readily via surfaces and self-inoculation to the eyes and nose, not only by droplets.