Dr. Greene’s Answer:
Most adults — but not all — have already had Hand Foot and Mouth and are not at risk. There are a few different strains of viruses that cause Hand Foot and Mouth though, so having had the illness once isn’t a guarantee. This leads many parents to ask, ‘Is hand foot and mouth disease contagious?’
Kids may be contagious just by being in the same room while they have a fever and for up to 24 hours after. The saliva can contain the virus for up to 2-3 weeks. The stool can contain the virus for 3-8 weeks or even more. Studies in daycare show that the great majority of spread, though, happens in the first 7 days of symptoms.
I don’t recommend keeping kids out of school beyond 24 hours after fever – because there are likely several kids in class with it anyway without the fever, who don’t even know they have it. Keeping kids out doesn’t appreciably change the spread. Kids may return to school once there is no fever, no drooling with open sores around the mouth and once their energy levels have returned.
But I do recommend keeping kids with Hand Foot and Mouth away from vulnerable adults, if possible:
- Affected kids should not be in the same room as vulnerable adults if they have a fever, plus 24 hours after the fever is gone.
- Affected kids should not share the same food or utensils with vulnerable adults while any sores are still present in the mouth or on the body.
- Vulnerable adults should not change diapers or aid with toileting assistance in affected kids for two months.
- Everyone should implement good hand-washing all the way around, after using the toilet and before eating or drinking or putting hands in the mouth.
If others in the family do get sick, the first symptoms usually occur 3-5 days after getting the virus – and they become contagious about the same time (unlike chickenpox, where you are contagious 24-48 hours before symptoms).
Saguil A, et al.. Hand-Foot-and-Mouth Disease: Rapid Evidence Review. Am Fam Physician. 2019 Oct 1;100(7):408-414.