Quick Answer
Most vaccine side effects are mild and expected - they often show the vaccine is working. Common reactions include low-grade fever (bukhar), injection site pain and swelling, and temporary fussiness or sleepiness. These typically resolve within 24-48 hours without any treatment. Serious reactions are rare, and the benefits of vaccination far outweigh the risks — but it helps to know the danger signs (see the emergency section below).
How Vaccines Protect Your Baby
Vaccines work by introducing a weakened or inactive form of disease-causing germs (or parts of them) into your baby’s body. This triggers the immune system to produce antibodies - the body’s natural disease fighters. Once these antibodies are formed, they remain ready to protect your child if they ever encounter the actual disease.
Think of it like a practice drill - your baby’s body learns to fight the disease without actually getting sick. This is why vaccines are considered one of the safest and most effective ways to protect children from serious illnesses.
Before Going for Vaccination: Tips for Indian Parents
Prepare in Advance
- Keep the vaccination card (teeka card) ready - Maintain proper records of all vaccines given and their dates
- Feed your baby well before the appointment - Babies often become bukhar (feverish), tired, or cranky afterward and may not feed properly
- If your baby is on formula doodh - Carry a prepared bottle or formula powder with sterile water. Brands like NAN Pro, Lactogen, or Similac are commonly used
- Dress baby in loose, comfortable clothes - Easy access to the thigh or upper arm makes injection easier
What to Carry
- Vaccination card
- Formula or expressed breastmilk if needed
- Extra diaper and change of clothes
- A comfort toy or pacifier
Common Vaccine Reactions: Age-by-Age Guide
General Symptoms (All Ages)
These reactions are normal and show the vaccine is working:
- Mild irritability and crying - Baby may be more fussy than usual
- Restlessness or extra sleepiness - Both are normal responses
- Decreased appetite - Baby may feed less for a day or two
- Low activity levels - Baby may seem tired Good news: These symptoms usually disappear within 24-48 hours and don’t need any special treatment.
Injection Site Reactions
What to expect:
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Pain, redness, and swelling at the shot location (usually thigh for babies)
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May feel warm to touch
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Baby may cry when the area is touched How to treat:
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Apply a COOL compress for the acute reaction - For pain, redness and swelling in the first 1-2 days, hold a cool, damp clean cloth (or a wrapped cold pack — never ice directly on the skin) on the spot for about 10 minutes, as needed. Cool helps settle the inflammation [CDC, Before, During, and After Shots].
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Move the leg/arm gently - Using the limb normally helps the soreness ease.
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For a residual painless lump (later): Once the acute swelling has settled, a warm compress 2-3 times a day may help a firm, painless lump that lingers for a few weeks.
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About paracetamol: A comfortable baby with mild soreness doesn’t need medicine. If your baby is clearly uncomfortable or not feeding because of pain, you may give weight-based paracetamol for comfort (see dosing below). The one thing to avoid is giving paracetamol routinely before the shot to a well baby to prevent fever, as that may slightly reduce the vaccine response [AAP/ACIP].
For itchy hives at injection site: Apply doctor-prescribed 1% hydrocortisone cream only if recommended by your pediatrician.
Managing Vaccine Fever (Bukhar)
Vaccine-induced fever is common and usually not harmful - it is part of your baby’s immune response.
⚠️ In a baby under 3 months, ANY fever of 100.4°F (38°C) or higher is a medical emergency — see a doctor the same day, even at night. Do not give paracetamol and wait. This applies even after a vaccine.
Timeline:
- Most vaccine fevers start within 12 hours of the shot
- Usually last 1-2 days
- Typically low-grade (100-102°F or 37.8-39°C) What to do:
Treat fever for your baby’s comfort, not to chase a particular number on the thermometer:
- A comfortable, playful baby with a low-grade fever can simply be left alone — no medicine needed.
- If your baby is clearly uncomfortable, very fussy, or not feeding because of fever or pain, you may give weight-based paracetamol.
- If fever goes above 103°F (39.5°C), or you are worried at any temperature, contact your pediatrician.
Paracetamol is dosed by your baby’s weight, not age: 15 mg/kg per dose, no more often than every 4–6 hours, maximum 4 doses (60 mg/kg) in 24 hours. Syrup strengths differ — Calpol/Crocin come as 120 mg/5 ml and 250 mg/5 ml, so always check the bottle. Do not give to a baby under 3 months without a doctor seeing them first. Confirm the exact mL with your pediatrician.
Hydration is Key:
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For babies under 6 months: Give only breastmilk or formula doodh (NAN, Lactogen, Similac)
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For babies over 6 months: Offer extra breastmilk, formula, or small sips of water
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Encourage unlimited cool fluids to prevent dehydration Comfort measures:
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Dress baby in light, everyday clothes
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If baby has chills (thandi lag rahi hai), wrap in a light blanket until comfortable
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Keep room at comfortable temperature
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Extra cuddles and skin-to-skin contact help!
Common Concerns About Vaccines
Is There Mercury in Vaccines?
No evidence of harm has been found from the small amounts of thimerosal, a mercury-based preservative, historically used in vaccines. In many high-income countries it was removed from most childhood vaccines around 2001 as a precaution; some multidose vials used in India and elsewhere may still contain it, and these remain safe to use according to the WHO Global Advisory Committee on Vaccine Safety [WHO GACVS].
Do Vaccines Cause Autism?
No. Multiple large studies across countries including India, US, and Denmark have found no link between vaccines and autism. Organizations like WHO, CDC, and Indian Academy of Pediatrics confirm vaccines do not cause autism.
Emergency: Get Help Immediately
A severe allergic reaction (anaphylaxis) after a vaccine is rare, but when it happens it usually begins within minutes to a few hours — which is why most clinics ask you to wait 15–20 minutes at the centre after the shot. It needs action in minutes, not a clinic appointment.
🚨 Call 112 (national emergency) or 108 (ambulance), or go straight to the nearest hospital, if you see: difficulty or noisy breathing; swelling of the face, lips or tongue; widespread hives with vomiting; pale, grey or blue skin; floppiness or unresponsiveness; or a seizure. These can be a severe allergic reaction (anaphylaxis). If an adrenaline auto-injector has been prescribed, use it first, then go. Do not wait for a clinic appointment.
A vaccine can occasionally trigger a brief febrile seizure (jerking or stiffening with a high fever). It is usually short and benign, but you cannot tell that in the moment — treat any seizure as an emergency using the steps above: lay the baby on their side, do not put anything in the mouth, and call 112/108.
When to Call Your Doctor
Contact your pediatrician the same day (not an emergency, but don’t wait it out) if:
- A new fever starts more than 24–48 hours after the shot, or any fever lasts more than 3 days
- Any fever in a baby under 3 months (this is always an immediate call — see the fever section above)
- Redness becomes more painful after day 3
- Pain or redness continues beyond 7 days
- Redness spreads beyond 2 inches (5 cm) from the injection site
- Baby is extremely drowsy and difficult to wake
- Baby has high-pitched, unusual crying
- You notice any reaction that worries you
(Red-flag thresholds above follow standard immunization-reaction triage protocols, e.g. Children’s Colorado.)
Remember: Serious reactions are rare and most babies have only mild symptoms or none at all — but the danger signs above are worth knowing. When in doubt, always consult your pediatrician.
Tips for a Smooth Post-Vaccination Recovery
- Keep baby comfortable - Extra feeding sessions, cuddles, and rest
- Watch for reactions - Note the time they start and how long they last
- Don’t skip feedings - If baby refuses breast, try offering formula doodh from botal (bottle)
- Maintain vaccination schedule - Mild reactions from previous vaccines are not reasons to delay future doses
- Take photos if you notice unusual reactions - helpful to show the doctor
Expert Insight: Our pediatricians note that fed is best — breast milk is preferred where possible, and formula is a valid choice that provides good nutrition when needed.
FAQs
Q: My baby is very cranky and not feeding after vaccination. Is this normal?
A: Haan, bilkul normal hai! Many babies become irritable and refuse feeds for 12-24 hours after vaccination. This is temporary. Keep offering breast milk or formula doodh frequently - even if baby takes smaller amounts more often. If baby refuses both breast and bottle for more than 8 hours, contact your pediatrician.
Q: Can I give formula along with breastmilk after vaccination?
A: Yes, absolutely. If your baby is not latching well due to fussiness, you can offer expressed breastmilk or formula (NAN Pro, Lactogen) from a bottle. Hydration is important, especially if baby has fever. Mixed feeding is perfectly fine during recovery.
Q: Should I give Calpol before vaccination to prevent fever?
A: Pediatricians generally recommend not giving paracetamol (Calpol) routinely before vaccination to a well baby, as giving it prophylactically may slightly reduce the vaccine response. Once symptoms are present, give paracetamol for comfort if your baby is clearly uncomfortable or not feeding — dosed by weight, as above — rather than to a fixed temperature number.
Q: Baby has a small lump at injection site - is this dangerous?
A: A small, firm lump at the injection site is common and normal. It may last for a few weeks but will gradually disappear. This is not dangerous. However, if the lump grows larger, becomes very painful, or shows signs of infection (pus, spreading redness), consult your doctor.
Q: Can I bathe my baby after vaccination?
A: Yes, you can give a normal bath. Use lukewarm water (na zyada garam, na thanda). Bathing can actually help soothe a fussy baby. Just avoid scrubbing the injection site.
This article was reviewed by a Babynama pediatrician. Last updated: February 2026
This article is general information for Indian parents, not a substitute for examination by your pediatrician. In an emergency, call 112 or 108.
Need personalized guidance? Book a consultation with our pediatricians or explore our Care Plans for 24/7 expert support!
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