School Exclusion for Infections

Authored by , Reviewed by Prof Cathy Jackson | Last edited | Meets Patient’s editorial guidelines

This leaflet provides brief information about common childhood infections and whether or not children should go to school, etc.

Doctors are often asked about incubation times for the common childhood infections, so that they can advise whether the child should go to school, etc. Incubation time is the time between coming into contact with the source of the infection and the symptoms showing. Infectivity is the length of time that you are infectious. Both of these can be variable, so the following is only a guide. Slightly fuller lists are provided by Public Health England, Health Protection Scotland, Public Health Wales and Public Health Northern Ireland.

Note: * indicates a notifiable disease. In the UK these are required (by law) to be reported to government authorities.

DiseaseIncubationInfectivityExclude UntilComments
Chickenpox11-20 daysUp to 4 days before (usually only 1 day) to 5 days after. 
Cases often transmit before appearance of rash.
5 days from the onset of rash.Traditionally excluded until all lesions are crusted but no transmission recorded after day 5.
Contacts with a weak immune system or who are pregnant should receive preventative treatment.

1-11 days (Usually 2-5 days)

Patients are probably not infectious if treated and diarrhoea has resolved.48 hours from last episode of diarrhoea.Exclude for 48 hours longer in children who are unable to maintain good personal hygiene.
Cold sores1-6 daysWhile lesions are moist.None.Highly infectious, especially amongst young children.
Avoid kissing.
Conjunctivitis3-29 days
Mean = 8
While active (direct contact).
Infective up to 2 weeks.
None.Transmission more likely in young children by direct contact - very few data.
Cryptosporidiosis*1-12 days (usually 7 days)12-14 days (may be as long as 1 month).48 hours from last episode of diarrhoea.Exclusion from swimming for 14 days after diarrhoea has settled.
Diarrhoea and vomiting8-10 days6-16 days.48 hours from last episode of diarrhoea or vomiting.Exclude for 48 hours longer in children who are unable to maintain good personal hygiene.
Glandular fever33-49 daysAt least 2 months.None.None.

Hand, foot and mouth disease

3-5 daysUp to 50% in homes and nurseries.None.Stool excretion continues for some weeks. Avoid infection in pregnant women.
Head licen/aWhile harbouring lice.None.Treatment needed for cases and contacts shown to have live head lice.
Hepatitis A*15-50 daysFrom 2 weeks before to 1-2 weeks after jaundice onset.Exclude until 7 days after onset of jaundice (or 7 days after symptom onset if no jaundice).Good hygiene needs emphasising.

Hepatitis B* Hepatitis C*


 See comment.None.These are blood-borne viruses and are not infectious through casual contact.
ImpetigoSkin carriage 2-33 days before development of impetigo (streptococci)High (streptococci).
Low (staphylococci).
Variable infectivity depending on causative bacteria.
Until lesions have healed or crusted or 48 hours after starting antibiotic treatment.Antibiotics speed healing and shorten the infectious period.
Measles*6-19 daysHighly contagious in the non-immune population.
A few days before to 6-18 days after onset of rash.
4 days from onset of rash.Check immunisation.
Risk of serious infection in people with a weak immune system (give preventative treatment).
MRSASkin carriageLow.None.Good hygiene, in particular handwashing, is important.
Mumps*15-24 days10-29 days.
Moderately infective in the non-immunised population.
5 days from onset of swelling.Preventable by vaccination.
RingwormVariesUntil lesions resolve.Exclusion not usually required.Good hygiene helps. Treatment is required.
Rubella*14-21 days1 week before to approximately 4 days after onset of rash.4 days from onset of rash.Preventable by immunisation. Check all female contacts are immune.
ScabiesVariesUntil mites and eggs are dead.Can return after first treatment.Risk of transmission is low in schools but outbreaks do occur.
Close contacts should also be treated.
Scarlet fever*1-3 daysModerate within families.
Low elsewhere.
Infective first 3 days of treatment.
24 hours after starting antibiotic treatment.Moderate within families.
Low elsewhere.
Shingles 14-16 daysReactivation of the virus that causes chickenpox but lower infectivity.5 days from the onset of the rash.If the rash can be covered, exclusion is not usually necessary. Contacts with a weak immune system or those who are pregnant should receive preventative treatment.
Slapped cheek disease13-18 days30% in families.
10-60% in schools.
None.Avoid infection in pregnant women and people with a weak immune system.
Threadwormsn/aUntil all worms are dead.None.Good hygiene helps.
Case and family contacts should be treated.
Tuberculosis*n/aUntil 14th day of treatment.Variable. Always consult the local health protection unit.See "references" below.
Warts and verrucasn/aNone.None.Care needed with verrucas in swimming pools, gymnasiums and changing rooms.
Whooping cough*7-10 daysMainly early catarrhal stage, but until 4 weeks after onset of cough paroxysms.
Shorten to 7 days if given antibiotics.
48 hours from commencing antibiotic treatment, or 21 days from onset of illness if no antibiotic treatment.Preventable by vaccination. Check immunisation of contacts.
Highly infectious in non-immune populations.

Clinical Editor's comments (September 2017)
Dr Hayley Willacy has noticed that Public Health England has recently updated its advice to schools and nurseries - see Further Reading below. This is a practical guide on infection prevention and control in schools, nurseries and other childcare settings. It is intended for staff working in these settings and reviews the general principles of infection control, how to manage cases of disease (including when an infected child/staff member should be excluded from their school/nursery in order to protect others) and when to seek specialist advice.


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