Infection Exposure Questions - Contagiousness  
  • 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.  Many common bacterial infections are not spread to others. Examples are ear, sinus, bladder, or kidney infections. Pneumonia also cannot be passed to others.  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

DISEASEINCUBATION PERIOD
(DAYS)
CONTAGIOUS PERIOD
(DAYS)
Skin Infections/Rashes:
Chickenpox10-212 days before rash until all sores have crusts (6 - 7days)
Fifth disease (Erythema infectiosum)4-147 days before rash until rash begins
Hand, foot, and mouth disease3-6Onset of mouth ulcers until fever gone
Impetigo (strep or staph)2-5Onset of sores until 24 hours on antibiotic
Lice7Onset of itch until 1 treatment
Measles8-124 days before rash until 4 days after rash appears
Roseola9-10Onset of fever until rash gone (2 days)
Rubella (German measles)14-217 days before rash until 5 days after rash appears
Scabies30-45Onset of rash until 1 treatment
Scarlet fever3-6Onset of fever or rash until 24 hours on antibiotic
Shingles (contagious for chicken pox)14-16Onset of rash until all sores have crusts (7 days) (Note: No need to isolate if sores can be kept covered.)
Warts30-180Minimally contagious
Respiratory Infections:
Bronchiolitis4-6Onset of cough until 7 days
Colds2-5Onset of runny nose until fever gone
Cold sores (herpes)2-12Footnote 1
Coughs (viral) or croup (viral)2-5Onset of cough until fever gone
Diphtheria2-5Onset of sore throat until 4 days on antibiotic
Influenza1-2Onset of symptoms until fever gone over 24 hours
Sore throat, strep2-5Onset of sore throat until 24 hours on antibiotic
Sore throat, viral2-5Onset of sore throat until fever gone
Tuberculosis6-24 monthsUntil 2 weeks on drugs (Note: Most childhood TB is not contagious.)
Whooping cough7-10Onset of runny nose until 5 days on antibiotic
Intestinal Infections:
Diarrhea, bacterial1-5Footnote 2 for Diarrhea Precautions
Diarrhea, giardia7-28Footnote 2 for Diarrhea Precautions
Diarrhea, traveler's1-6Footnote 2 for Diarrhea Precautions
Diarrhea, viral (Rotavirus)1-3Footnote 2 for Diarrhea Precautions
Hepatitis A14-502 weeks before jaundice begins until jaundice resolved (7 days)
Pinworms21-28Minimally contagious, staying home is unnecessary
Vomiting, viral2-5Until vomiting stops
   
Other Infections:
Infectious mononucleosis30-50Onset of fever until fever gone (7 days)
Meningitis, bacterial2-107 days before symptoms until 24 hours on IV antibiotics in hospital
Meningitis, viral3-6Onset of symptoms and for 1-2 weeks
Mumps12-255 days before swelling until swelling gone (7 days)
Pinkeye without pus (viral)1-5Mild infection, staying home is unnecessary
Pinkeye with pus (bacterial)2-7Onset of pus until 1 day on antibiotic eyedrops

Notes

  1. 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.

  2. 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.


Author and Senior Reviewer: Barton D. Schmitt, M.D.

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