Is strep throat contagious?
Last updated September 3, 2026.
Yes - strep throat spreads person to person through respiratory droplets, with illness starting 2 to 5 days after exposure, and households pass it around constantly. Untreated, you can spread it for weeks; on appropriate antibiotics, contagiousness drops sharply within about a day - hence the standard rule: stay home until fever-free and antibiotics are started, per your provider's guidance.
What to do
- Isolate the obvious routes. No shared cups, utensils, or toothbrushes while sick.
- Swap the toothbrush. Replace it a day or two into antibiotics.
- Follow the return rule. Fever gone and antibiotics started - then school or work per your provider.
- Finish the whole course. Stopping early invites relapse and complications like rheumatic fever.
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