In this article:
Why Some Vaccines Cause More Fever Than Others
The vaccines most likely to cause fever are:
- Pentavalent vaccine (6, 10, and 14 weeks): Given at government centres under India's Universal Immunisation Programme (UIP), this single shot covers five diseases: diphtheria, tetanus, pertussis, Hepatitis B, and Hib. The pertussis component is DTwP (whole-cell), which causes more fever and local redness than the acellular DTaP used at private clinics. Though both are equally effective, if your baby has a significant fever after DTwP, discuss switching to DTaP for remaining doses with your paediatrician.
- PCV (Pneumococcal Conjugate Vaccine): Given at 6, 10, and 14 weeks with a booster at 9 months under the IAP schedule, PCV frequently causes mild fever, particularly when given alongside other vaccines at the same visit.
- MMR (9–12 months): This is the one exception to the fever within 24 hours rule. MMR can cause a delayed fever and a mild rash that appear 7 to 12 days after the shot, not immediately. This is a vaccine reaction, not an infection.
What Temperature Is Normal After Vaccination?
| Temperature | What It Means |
| 37.5°C – 38°C (99.5°F – 100.4°F ) | Low-grade, common |
| 38°C – 39°C (100.4°F – 102.2°F ) | Mild fever, normal immune response |
| 39°C – 39.5°C (102.2°F – 103.1°F ) | Monitor closely; give paracetamol |
| Above 39.5°C (103°F or above) | Call your paediatrician |
Fever typically peaks around 6 hours post-vaccination and resolves within 1 to 2 days. A fever starting 3 to 4 days after the shot, unless it's the MMR, is likely a separate infection, not a vaccine reaction.
How to Manage Post-Vaccination Fever at Home
Here are some tips to manage this fever at home
- Dress your baby lightly: Avoid wrapping in extra layers or heavy blankets, as this traps heat and can worsen discomfort.
- Offer frequent feeds: Fever increases fluid loss. Breastfed babies should be nursed more often. For formula-fed babies, offer extra water or formula between feeds.
- Give paracetamol: Paracetamol syrup is the recommended choice for post-vaccination fever in babies. Always follow the dose advised by your paediatrician, as it is calculated based on your baby's weight.
- Keep the room comfortable: A fan or AC on a low setting is fine. Cool, damp sponging on the forehead can help if the fever is above 39.5°C and paracetamol has already been given.
- Expect 24 to 48 hours of fussiness: Disturbed sleep, reduced appetite, and clinginess are normal for 1 to 2 days after vaccination. Skin-to-skin contact and extra feeds help settle a distressed baby.
Current IAP guidance does not recommend giving paracetamol before vaccination to prevent fever. Studies show it may slightly reduce the vaccine's immune response. Give it only once a fever develops, as advised by your paediatrician.
When to See a Doctor
Most post-vaccination fevers are mild and resolve without medical intervention. Contact your paediatrician if:
- Fever rises above 103°F
- Fever lasts more than 48 hours
- Your baby is under 3 months old (any fever in a newborn requires immediate medical evaluation)
- Crying is continuous for more than 3 hours
- Swelling, redness, or a hard lump at the injection site
- Your baby becomes unusually drowsy or unresponsive
- A rash or hives appear within 15 to 30 minutes of the shot (this may indicate a rare allergic reaction)
- Your baby refuses to feed for more than 6 hours
With the right information and a few simple steps, managing post-vaccination fever at home is manageable. Remember, your paediatrician is always your best resource when something doesn't feel right.
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FAQs on Fever After Baby Vaccines: What's Normal and When to Worry
- Is it safe to vaccinate on schedule even if the baby has a fever after the last shot?
Yes. A fever after a previous vaccine dose is not a reason to delay the next one. Missing or delaying scheduled doses leaves your baby unprotected during that gap. Always discuss past reactions with your paediatrician before the next visit; they will advise accordingly, but will rarely recommend skipping a dose. - Can I give paracetamol before the vaccination to avoid fever?
No. IAP guidelines do not recommend prophylactic paracetamol before vaccination, as it may slightly reduce the immune response to the vaccine. Give it only if a fever develops after the shot. - My baby's fever started 10 days after the MMR vaccine. Is that a reaction or an illness?
A mild fever and measles-like rash can occur 7 to 12 days after the MMR vaccine. This is a known and expected vaccine reaction in some children and usually goes away on its own within 2 to 3 days.