We’ve all been there. The fever is down, maybe never to return, and there’s a birthday party your child has craved all week. After diagnosing an illness in the emergency department, we’ll often get the “contagious” question, with the subtext “So can I take her to the birthday party without being a bad parent?”
As with most medical issues, the answer is “it depends.” The easiest answer is when your child has swab or culture proven strep throat. Twenty-four hours after beginning antibiotics, your child is no longer infectious, hooray!1 For most other illnesses, the answer is less clear cut.
Coxackie virus, or hand foot and mouth disease, can have shedding of the enterovirus that causes it in your child’s poop for up to THREE MONTHS. Most viral illness will continue to have some infectious material in the saliva for a week or so, but if you can keep your child from licking another kid and train them not to share sippy cups, you’re probably ok.
The illnesses that make the most difference are those that can affect a baby of a pregnant woman who catches it from your child. Rubella is the biggest deal, as Zika-like birth defects happen when an under-immunized mom catches it. The other classic concern is Parvovirus B19. This is a common childhood illness causing “slapped cheeks” rash or “fifth’s disease” a day or so after the fever goes away. The disease is infectious while the child has a mild fever, and if a pregnant mother catches it rarely she could lose the baby. The good news is that once the slapped cheeks arise, the child is no longer infectious. However, if there are siblings who haven’t caught it yet, NO one is going to that party.
The best rule of thumb is to consider your child infectious until fever is gone for twenty-four hours, and continue to be vigilant about drool and poop for a week. Be aware if “Fifth’s disease” is circulating if your child could be around pregnant women, and feel secure with treated strep after 24 hours even if a low-grade temperature remains.
1The RED Book: report of the committee on Infectious diseases. Kimberlin DW, Brady MT eds.; Elk Grove Village, IL: American Academy of Pediatrics, 2015
Amy Baxter MD is a pediatric emergency physician and inventor of Buzzy Pain Relief. She lectures nationally and internationally on needle phobia, pain management, sedation, and child abuse.