Q: My child has a 37.7°C fever after getting vaccinated yesterday. Should I give fever medication again?
Updated: 23 hours ago
Medically reviewed by Sang Hyun Ahn, MD
Content edited by Myeongchan Kim, MD
This post is a dramatization of a question and answer session experienced by our actual medical reviewers. Please note that this content is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
Question:
My child received the Japanese encephalitis and Hepatitis A vaccines yesterday. They developed a fever, and I gave them fever-reducing medication twice. Today, their temperature is lingering around 37.7°C (99.9°F) and isn't dropping. Should I give them another dose of fever reducer?
Answer:
A low-grade temperature of 37.7°C (99.9°F) within 24 to 48 hours following a vaccination is a very common and expected sign that the immune system is actively working to build protection.
Here is what you should consider when deciding whether to give medication:
Treat the Child's Comfort, Not Just the Number
37.7°C is not dangerous: A low-grade fever is part of the body's natural immune response. You do not need to treat the number on the thermometer alone.
When to hold off: If your child is alert, playing well, eating, and sleeping normally, you do not need to give a fever reducer.
When to give medicine: Only consider another dose of fever-reducing medication (such as acetaminophen or ibuprofen, appropriate for their age) if your child is clearly uncomfortable, fussy, unable to sleep, or refusing fluids.
Home Care Tips
Dress lightly: Dress your child in a single layer of loose, comfortable clothing. Keep the room at a comfortable temperature, and avoid bundling them in thick blankets.
Stay hydrated: Encourage frequent, small amounts of fluids, such as water, breast milk, or formula, to prevent dehydration.
When to Contact Your Pediatrician
Seek medical evaluation if you notice any of the following warning signs:
The fever reaches 38.5°C (101.3°F) or higher, or lasts longer than 48 hours after vaccination.
Your child is unusually lethargic, refuses to make eye contact, or is inconsolably irritable.
There are signs of dehydration, such as no wet diapers or urination for 8 hours or more.
The injection site develops expanding redness, severe swelling, or excessive warmth.
In summary, if your child is acting well and remains comfortable, it is best to hold off on medication and let their immune system do its job. However, if they show noticeable discomfort or if the fever persists beyond 48 hours, consult your pediatrician.
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
