Fever After Baby Vaccines: What Is Normal and When to Call

A mild fever, a sore injection site and a fussy, sleepy baby are common for one to two days after vaccines. They mean the immune system is responding. Offer extra feeds, dress your baby lightly and give pain relief if your doctor advises it. Call a doctor if the fever is high, lasts more than 48 hours or your baby seems unwell in any other way.

Is a fever after vaccines normal?

Yes. A low-grade fever is one of the most common reactions to childhood vaccines, and it is a sign that your child’s body is building protection. Most reactions start within 24 hours of the injection and settle by themselves within one to two days. This is also true for the combined vaccines given at 2, 4 and 6 months, such as the 6-in-1 vaccine.

A fever means a temperature of 38°C or above. Many babies after vaccines have a temperature between 37.5°C and 38.5°C.

What other reactions are common?

These are all usual and short-lived:

• Soreness, redness or swelling where the injection went in, sometimes with a small firm lump that can take a few weeks to fade
• Fussiness and crying for a day, more than usual
• Sleepiness, or the opposite, being unsettled at night
• A smaller appetite for a feed or two
• A mild rash that fades on its own

Different vaccines tend to cause different reactions. The live vaccines, MMR and chickenpox, can cause a fever or a mild rash 5 to 12 days after the injection, not on the first day. This catches many parents out. It is expected and does not mean the vaccine has gone wrong. Rotavirus vaccine is given by mouth and may cause fussiness or loose stools for a day or two.

How do I check my baby’s temperature?

Use a digital thermometer. For babies, place it under the arm, or use an ear or forehead thermometer as its instructions say. Do not use a glass thermometer. Take the temperature when your baby is calm and not just after a feed or a warm bath. Our guide to dealing with a fever explains it in more detail.

What helps my baby feel better?

• Offer more feeds, breast or bottle, and more fluids for older children. Fever uses up fluid.
• Dress your baby lightly and keep the room comfortably cool. Do not wrap a baby with a fever in extra layers.
• Hold and comfort your baby. Skin-to-skin contact and cuddles help.
• Cool the injection site with a clean, cool, damp cloth if it is sore. Do not rub it.
• Give pain relief if needed. Paracetamol can ease pain and fever. Ibuprofen can be used in babies older than three months. Follow the label dose for your baby’s weight, or ask your pediatrician or pharmacist. Never give aspirin to a child.

Do not give paracetamol routinely before the injection “just in case”. Some schedules advise it for particular vaccines, so ask your pediatrician what applies to your baby.

When is a fever after vaccines not normal?

Contact your doctor if:

• the fever is 39°C or higher in a baby aged 3 to 6 months, or 40°C or higher at any age
• the fever lasts more than 48 hours or comes back
• your baby has a fever and is under 3 months old: a temperature of 38°C or above at this age always needs prompt medical review, whatever the cause
• your baby cries inconsolably for more than 3 hours, or has an unusual high-pitched cry
• redness or swelling at the injection site spreads or gets worse after 48 hours, or looks infected
• your baby is not feeding, has far fewer wet nappies, or seems unusually floppy or hard to wake
• you simply feel something is wrong. You know your baby well.

What about a serious allergic reaction?

Serious allergic reactions to vaccines are very rare, and they happen soon after the injection, usually within minutes to a few hours. Signs include hives or a widespread rash, swelling of the face, lips or tongue, wheezing or difficulty breathing, and a pale, limp child. This is an emergency: call 998 or go to the nearest emergency department.

If you notice anything unusual in the hours after you get home, call us or go to an emergency department straight away.

Can a fever after a vaccine cause a seizure?

Rarely. Some young children have a seizure when their temperature rises quickly, whether the cause is a vaccine or an infection. These are called febrile seizures. They are frightening to see but are usually brief and do not cause lasting harm. See our guide to febrile seizures for what to do and when to call.

Should I delay the next vaccine if my baby had a fever?

A mild fever after a vaccine is not a reason to skip the next dose. If your child had a stronger reaction than expected, tell your pediatrician before the next visit, so the doctor can advise. A mild cold or low-grade temperature on the day of a vaccine usually does not mean it must be postponed, but your doctor decides. Our guides to the UAE baby vaccine schedule and the UAE childhood vaccination schedule list the doses and ages.

How can I make the vaccine visit easier?

• Feed your baby shortly before the visit, if they are due a feed.
• Hold your baby close during the injection, and offer a feed or a cuddle straight afterwards.
• Bring a favourite toy or blanket, and stay calm. Babies pick up on your mood.
• For older children, explain what will happen in simple words and be honest that it may sting for a moment. Distraction helps. We also offer virtual reality headsets to distract children during vaccines and blood tests.

The NHS and the American Academy of Pediatrics both give clear guidance on the common reactions to childhood vaccines.

When to see a doctor

How we can help at myPediaclinic

Our pediatricians, Dr. Tala Belbeissi and Dr. Medhat Abu-Shaaban, give vaccines and blood tests through our vaccination service. We explain what to expect after each vaccine, check your child’s record against the national schedule, and see your baby if you are worried about a reaction. Dr. Tala Belbeissi trained in the US and Dubai, and Dr. Medhat Abu-Shaaban is a Fellow of the American Academy of Pediatrics. Both consult in English and Arabic.

Our guide to vaccination with virtual reality explains how we help older children stay calm.

Frequently asked questions