Is My Child Contagious?

Does it seem like your children are always “catching” a cold from other kids in their preschool or neighborhood? While you can’t prevent your kids from ever getting sick, you can teach them good health habits, like hand washing, that may lessen their chances of becoming ill. Infectious diseases are caused by germs, such as viruses, bacteria and parasites. Contagious or communicable diseases are those that can be spread from one person to another, usually through bodily contact with a person or object. Infants and toddlers are highly susceptible to contagious diseases because they haven’t been exposed to many of the most common germs. Because of this, they haven’t built up resistance or immunity to them. Also, young children have many habits that promote the spread of germs. For example, they often finger their nose or put their fingers or other objects in their mouths, allowing germs easy entry to and exit from the body.

Infectious diseases that commonly occur among children are often contagious and may spread very easily from one person to another. The term incubation is used to describe the period when the infection is developing, but not yet symptomatic. Communicability is the period when the disease is contagious. Some diseases are communicable before you even see the first symptom and others can be spread when symptoms are apparent (chickenpox) or after symptoms have disappeared.

Most infections are spread from person to person. Germs are present on the skin or in the body fluids of an infected person. Germs are then either passed directly (coughing on hands) or indirectly (by contaminating the environment). Usually, germs are present on the skin or in infectious body fluids, such as discharge from the eyes, nose, mouth or intestinal tract, allowing the germs to travel through the air (they only travel less than 3 feet so close contact is important) and/or land on a surface. And in order for a person to become sick, that person, when not immune to the germ, must come in contact with or be exposed to the germs in a way that leads to infection. Germs need a way to get into the body through an opening, such as the eyes, nose, mouth or genitals.

Preventing the needless spread of illness is important, so determining when it’s safe for your child to return to school after an illness can be tricky. The chart on the back will give you an idea of the incubation and contagious period for some common illnesses. This chart should be used as a general guideline and should not replace the advice of your pediatrician.


Bronchiolitis Spread via respiratory droplets through sneezing or coughing  2 to 10 days  Onset of cough until 7 to 10 days 
Chickenpox (Varicella) Airborne or via skin contact with lesions  10 to 21 days  2 days before rash appears until all sores have crusted 
Colds Spread via respiratory droplets or direct contact with infected person or object  2 to 4 days  Onset of runny nose until fever is gone

Croup (viral) Spread via respiratory droplets or contact with infected person or object  2 to 6 days  Onset of cough until fever is gone
Diarrhea Contact with feces  Depends on causative agent (bacterial 1 to 7 days; viral 1 to 4 days)  Depends on causative agent; usually until stools are formed. (See specific agents)
Fifth Disease (Parvo virus) Spread via respiratory droplets  Usually 4 to 14 days, but can be as long as 21 days  7 days before rash until rash begins 
Hand-foot-mouth (Coxsackie) Spread via respiratory droplets, fecal/oral contact or fluid from blisters  3 to 6 days  Onset of mouth ulcers until fever is gone (respiratory tract shedding usually 1 week; fecal can be several weeks)
Hepatitis A Fecal contact  15 to 50 days  1 to 2 weeks before jaundice begins until 1 week after onset of jaundice
Hepatitis B Contact with infected blood/body fluids  45 to 160 days  Indefinite period. If Hepatitis e antigen is positive, at risk for transmission 
Herpes Simplex Oral/genital skin contact  2 days to 2 weeks  Initial infection: 1 week to several weeks (oral/genital). Recurrent infection: 3 to 4 days
Impetigo Direct skin contact with lesion and contact with infected objects  7 to 10 days  Onset of sores until 1 day on antibiotics
Influenza Spread via respiratory droplets or contact with infected person or object  1 to 4 days  24 hours before onset of symptoms until fever is gone, about 7 days
Lice Spread via contact with skin or hair  10 to 14 days  Onset of itch until 24 hours after first treatment
Meningococcus Spread via respiratory droplets  1 to 10 days  7 days before symptoms to 24 hours after treatment begins
Mononucleosis Contact with infected saliva  30 to 50 days  Undetermined, but usually 6 weeks
MRSA Spread via contact with infected person, person who is a carrier of the disease, or contaminated surface.  One to 10 days  Varies depending on whether infection is active and if person is seeking treatment 
Pertussis (whooping cough) Spread via respiratory droplets  Five to 21 days  Two weeks after onset of cough or until five days on antibiotics
Pink-eye or Conjunctivitis (bacterial) Spread via contact with eye drainage
2 to 7 days  Onset of pus until symptoms have resolved
Rotavirus Direct or indirect contact with infected people  2 to 4 days  Before onset of diarrhea until 10 to 12 days after onset
Salmonella, Shigella, Campylobacter Fecal contact  Salmonella - 12 to 36 hours
Shigella & Campylobacter - 1 to 7 days 
Contagious until diarrhea is resolved; sometimes with prolonged excretions with salmonella
Scabies Contact with clothing, bedding or skin of infected animal or person  4 to 6 weeks (previous exposure 1 to 4 days)  Onset of itch until one treatment completed
Scarlet fever Spread via airborne respiratory droplets and direct contact  1 to 2 days  Onset of fever or rash until 1 day on antibiotics
Sore throat (viral) Spread via respiratory droplets  2 to 5 days  Onset of sore throat until fever is gone 
Strep throat Spread via respiratory droplets  2 to 5 days  Onset of sore throat until 1 day on antibiotics 

2006 Red Book, Report of the Committee on Infectious Disease, American Academy of Pediatrics

Airborne - droplets nuclei that remain suspended in the air for long periods
Respiratory droplets - droplets propelled for a short distance, such as talking, sneezing, coughing, etc.

Bookmark and Share

iGrow iGrow
Sign up for our parent enewsletter
    Contact Us

    330-543-1000 (operator)

    (8 a.m.-4:30 p.m.)


    find a location
    Find a location Type the first 3-5 letters of a specialty, service or location:
    Or, view: a map, a list of all locations, locations by city or locations near me.
    find a doctor
    Find a doctor Type the first 3-5 letters of the name, location or specialty:
    Or, view a list of all doctors by name, location and specialty.