How Long Are You Contagious? Flu, COVID, Strep, Colds, Pink Eye, Stomach Bugs and More

Most common illnesses are most contagious in the first few days of symptoms, and sometimes a day or so before. A good general rule for going back to work or school is: no fever for 24 hours without fever medicine, and symptoms getting better. Some infections have their own rules: strep is no longer contagious after about 12 to 24 hours on antibiotics, and stomach bugs like norovirus need 48 hours after the vomiting and diarrhea stop. Schools, daycares and workplaces may have their own policies, so check those too.

Quick guide

• Flu: contagious from a day before symptoms to about 5 to 7 days after they start, longer in young children. Back when fever-free for 24 hours and improving.
• COVID: most contagious in the first few days of symptoms. Back when fever-free for 24 hours and improving, with extra precautions, like a mask, for the next 5 days.
• RSV: usually contagious for 3 to 8 days; infants and people with weak immune systems can spread it for up to 4 weeks.
• Common cold: most contagious in the first 2 to 3 days; can spread for up to 2 weeks.
• Strep throat: contagious until about 12 to 24 hours after starting antibiotics. Without treatment, it can spread for 2 to 3 weeks.
• Sinus infection: the infection itself isn't usually contagious, but the cold virus that often causes it is.
• Pink eye: viral pink eye is contagious while the eye is red and watery, often 1 to 2 weeks. Bacterial pink eye stops being contagious about 24 hours after starting antibiotic drops. Allergic pink eye isn't contagious.
• Norovirus and stomach bugs: most contagious while sick and for 3 days after; stay home until 48 hours after vomiting and diarrhea stop.
• Hand, foot and mouth disease: most contagious in the first week; the virus can stay in stool for weeks.
• Mono: spreads through saliva for weeks to months, but people usually don't need to stay home once they feel well enough.
• Bronchitis: the virus behind it is contagious for a few days to a week; the cough can last longer.

Back to work or school: the general rules

• No fever (100.4°F or higher) for 24 hours without fever-reducing medicine
• Symptoms are improving overall
• No vomiting or diarrhea for 48 hours, after a stomach bug
• At least 12 to 24 hours of antibiotics, for strep or bacterial pink eye
• Able to take part in normal activities

Food handlers, childcare workers and healthcare workers often have stricter rules.

Lowering the chance of spreading it

• Wash your hands often, with soap and water after a stomach bug, since hand sanitizer doesn't work well against norovirus
• Cover coughs and sneezes
• Don't share cups, towels or utensils
• Clean shared surfaces
• Wear a mask around others for a few days after a respiratory illness

Why a test can help

Knowing what you have changes how long you're contagious and whether treatment can help. At AfterOurs, a clinician can test for flu, COVID, RSV, strep and mono during the same visit. Our posts on flu, COVID or RSV, the rapid strep test, pink eye and norovirus go into more detail.

At an AfterOurs clinic, a standard self-pay visit is $175, a visit with a rapid test is $250, and a self-pay in-clinic visit never costs more than $330. A telehealth visit is $75. We contract with all major commercial and government plans, including Colorado Medicaid and Medicare. See our rapid testing page and the cost and insurance page.

Call 911 or go to the ER if you or your child has trouble breathing, chest pain, a stiff neck with fever, confusion, signs of serious dehydration, or a baby under 3 months has a fever of 100.4°F or higher.

Where to find us

Four clinics across metro Denver, all ages welcome, se habla español:

• Hampden (Southeast Denver): 8 AM–11 PM daily
• Littleton: 8 AM–11 PM daily
• Thornton: 8 AM–11 PM daily
• Highlands: Mon–Fri 5–11 PM, Sat–Sun 8 AM–11 PM

Walk in, or book online.