Infection Exposure Questions

This topic includes information about transmission of common infections. How long to stay out of school or child care is covered.
Incubation Period. Time it takes to start having symptoms after contact with infection.
Contagious Period. Time during which a sick child's disease can spread to others. Sometimes, children can return to school before this period is over.
Infections that cannot be spread to others, but there are a few exceptions. Your child's doctor will tell you for sure. Many common bacterial infections are not spread to others. Examples are ear, sinus, bladder, or kidney infections. Most pneumonia in children also can't be passed to others, but there are a few exceptions. Your child's doctor will tell you for sure. Sexually transmitted diseases are usually not spread to children. But, they can be spread if there is sexual contact or shared bathing.

Infection Exposure Table

DISEASE	INCUBATION PERIOD (DAYS)	CONTAGIOUS PERIOD (DAYS)
Skin Infections/Rashes:
Chickenpox	10-21	2 days before rash until all sores have crusts (6-7 days)
Fifth disease (Erythema infectiosum)	4-14	7 days before rash until rash begins
Hand, foot, and mouth disease	3-6	Onset of rash until fever gone. If widespread blisters, return after blisters are dry (6-7 days).
Impetigo (strep or staph)	2-5	Onset of sores until 24 hours on antibiotic
Lice	7	Onset of itch until 1 treatment
Measles	8-12	4 days before rash until 4 days after rash appears
Mpox (monkeypox)	5-21	Onset of symptoms until all crusts on sores have fallen off (2-4 weeks)
Roseola	9-10	Onset of fever until fever gone for 24 hours
Rubella (German measles)	14-21	7 days before rash until 5 days after rash appears
Scabies	30-45	Onset of rash until 1 treatment
Scarlet fever	3-6	Onset of fever or rash until at least 12 hours on antibiotic and fever is gone
Shingles virus (causes chickenpox in others, not shingles)	14-16	Onset of rash until all sores have crusts (7 days) (Note: no need to isolate if sores can be kept covered.)
Warts	30-180	Minimally contagious
Respiratory Infections:
Bronchiolitis	4-6	Onset of cough until 7 days
Colds	2-5	Onset of runny nose until fever gone
Cold sores (herpes)	2-12	Footnote 1
Coughs (viral) or croup (viral)	2-5	Onset of cough until fever gone
COVID-19	2-14	Onset of symptoms until fever gone and at least 10 days have passed
Influenza	1-2	Onset of symptoms until fever gone
Sore throat, strep	2-5	Onset of sore throat until at least 12 hours on antibiotic and fever is gone
Sore throat, viral	2-5	Onset of sore throat until fever gone
Tuberculosis	6-24 months	Until 2 weeks on drugs (Note: most childhood TB is not contagious.)
Whooping cough	7-10	Onset of runny nose until 5 days on antibiotic
Intestinal Infections:
Diarrhea, bacterial	1-5	Footnote 2 for Diarrhea Precautions
Diarrhea, giardia	7-28	Footnote 2 for Diarrhea Precautions
Diarrhea, traveler's	1-6	Footnote 2 for Diarrhea Precautions
Diarrhea, viral (Rotavirus)	1-3	Footnote 2 for Diarrhea Precautions
Hepatitis A	14-50	2 weeks before jaundice begins until jaundice resolved (7 days)
Pinworms	21-28	Minimally contagious, staying home is unnecessary
Vomiting, viral	2-5	Until vomiting stops
Other Infections:
Infectious mononucleosis	30-50	Onset of fever until fever gone (7 days)
Meningitis, bacterial	2-10	7 days before symptoms until 24 hours on IV antibiotics in hospital
Meningitis, viral	3-6	Onset of symptoms and for 1-2 weeks
Mumps	12-25	5 days before swelling until swelling gone (7 days)
Pinkeye without pus (viral)	1-5	Mild infection, staying home is unnecessary
Pinkeye with pus (bacterial)	2-7	Onset of pus until 1 day on antibiotic eyedrops

Notes

Cold sores: less than 6 years old, contagious until cold sores are dry (4-5 days). No isolation if sores are on part of body that can be covered. More than 6 years old, no isolation necessary if beyond touching, picking stage.

Diarrhea Precautions: contagious until stools are formed. Stay home until fever is gone, diarrhea is mild, blood and mucus are gone, and toilet-trained child has control over loose stools. Shigella and E-coli 0157 require extra precautions. Consult your child care provider regarding attendance restrictions.

Respiratory Infections: many can also be contagious during the 2 days before symptoms start. For that reason, spread is difficult to control.

When to Call for Infection Exposure Questions

When to Call for Infection Exposure Questions

Reviewed: 2/12/2025 Updated: 1/25/2025