Baby Vaccine Side Effects: What's Normal and When to Worry
Quick Answer: Most post-vaccination symptoms are completely normal and actually show that your baby's immune system is working! Mild fever (up to 101°F), fussiness, and soreness at the injection site are common and usually resolve within 1-3 days. These temporary discomforts are a small price for protecting your baby from serious diseases. You're doing a great job, mummy-papa!
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Why Do Reactions Happen After Vaccination?
Watch: Always look for this early hunger cues.Do you feed your baby only after they start crying?
Vaccines work by teaching your baby's immune system to recognize and fight diseases. When the immune system "wakes up" to learn, it sometimes causes mild, temporary side effects.
Think of it this way: Just like how your body might feel tired after a workout, your baby's immune system is "working out" after a vaccine!
Reassurance: These reactions are signs that the vaccine is working and your baby's body is building protection.
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Common Mild Symptoms (Normal - Don't Worry!)
These symptoms are expected and usually last 1-3 days:
At the Injection Site (Teeka Ki Jagah Par)
Symptom
What You'll See
Duration
**Redness**
Pink or red patch around injection
1-3 days
**Swelling**
Slight puffiness
1-3 days
**Tenderness**
Baby cries when touched there
1-2 days
**Small lump**
Painless, hard nodule
May last weeks - this is okay!
General Symptoms
Symptom
What's Normal
Duration
**Low fever**
Up to 101°F (38.3°C)
1-2 days
**Fussiness**
More crying/clingy than usual
1-2 days
**Sleepiness**
Sleeping more than usual
24-48 hours
**Less appetite**
Not feeding as much
1-2 days
**Mild rash**
After MMR vaccine (7-10 days later)
Fades on its own
Note on timing: Most reactions occur within 24-48 hours of vaccination. MMR vaccine may cause mild rash 7-10 days later.
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How to Comfort Your Baby After Vaccination
For Local Soreness (Injection Site Pain)
What helps:
Apply clean, cool, damp cloth gently on the sore area
Avoid pressing or massaging the area
Allow gentle movement of the limb
Dress baby in loose, soft clothing
Don't apply any creams unless doctor advises
What to avoid:
Don't apply ice directly
Don't massage vigorously
Don't apply home remedies (turmeric paste, etc.) on injection site
For Mild Fever and Discomfort
Step 1: Check with your pediatrician about paracetamol
Don't give any medicine without doctor's advice
If advised, use infant paracetamol syrup (Crocin, Calpol, etc.)
Follow dosage based on baby's WEIGHT, not age
Use the measuring cup provided - not household spoons!
Indian brand reference (always confirm dose with doctor):
Paracetamol syrup 125mg/5ml is common for infants
Dose is typically 10-15mg per kg of body weight
Step 2: Keep baby hydrated
Offer more breastfeeds (maa ka doodh is the best medicine!)
Formula-fed babies: offer small, frequent feeds
Older babies: offer water sips
Step 3: Dress lightly
Light cotton clothes
Don't overdress even with fever
Keep room comfortably cool
Step 4: Extra love and comfort
More cuddles and skin-to-skin contact
Gentle rocking or swaddling
Quiet, calm environment
Nursing on demand
For Fussy Baby
Offer the breast or pacifier
Gentle rocking in your arms
Soft singing or white noise
Skin-to-skin contact (kangaroo care)
Be patient - this phase passes quickly!
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Which Vaccines Cause Which Reactions?
Vaccine
Common Reactions
Timing
**DTaP/DPT**
Fever, fussiness, soreness
24-48 hours
**Polio (IPV)**
Usually none, mild soreness
24 hours
**Hepatitis B**
Mild soreness
24-48 hours
**BCG**
Small lump that may ulcerate - NORMAL
2-6 weeks
**MMR**
Mild fever, rash
7-10 days later
**Rotavirus (oral)**
Mild diarrhea, fussiness
1-2 days
**Pneumococcal (PCV)**
Fever, irritability
24-48 hours
BCG special note: The BCG vaccine (given at birth) causes a small lump that may form a pustule and even a small scar. This is COMPLETELY NORMAL and expected!
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When to Call the Doctor (Warning Signs)
Seek IMMEDIATE Medical Care If:
These symptoms are rare but need urgent attention:
High fever:
Temperature above 102°F (39°C)
ANY fever in baby under 3 months old
Fever lasting more than 3 days
Severe reactions:
Inconsolable crying for 3+ hours
Seizures or convulsions (fits)
Extreme lethargy - difficult to wake up
Limp, unresponsive
Signs of allergic reaction (anaphylaxis - very rare):
This happens within minutes to 2 hours of vaccination:
Difficulty breathing or wheezing
Swelling of face, lips, or throat
Widespread hives (itchy rash all over)
Unusual paleness
Fast heartbeat
Dizziness or fainting
Call emergency (100/112) immediately or rush to nearest hospital!
Trust your instincts! If something seems wrong, it's always okay to call your doctor.
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Vaccine-by-Vaccine Schedule (Indian Context)
Here's when to expect vaccines in India (IAP schedule):
Age
Vaccines
Expected Reactions
**Birth**
BCG, OPV, Hep B
BCG lump normal
**6 weeks**
DTaP, IPV, Hep B, Rota, PCV
Fever, fussiness common
**10 weeks**
DTaP, IPV, Rota, PCV
Fever, fussiness common
**14 weeks**
DTaP, IPV, Rota, PCV
Fever, fussiness common
**6 months**
Hep B, OPV
Usually mild
**9 months**
MMR
Possible rash 7-10 days later
**12 months**
Hep A, Varicella
Mild fever
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Frequently Asked Questions
Q: Should I give paracetamol before vaccination to prevent fever?
A: Most pediatricians don't recommend giving paracetamol BEFORE vaccination. Some research suggests it may slightly reduce the immune response. Give only if fever develops and doctor advises.
Q: Can I breastfeed right after vaccination?
A: Yes! Breastfeeding during or immediately after vaccination actually helps calm baby and may reduce pain. Maa ka doodh is the best comfort!
Q: My baby slept a lot after the vaccine. Is this normal?
A: Yes, increased sleepiness for 24-48 hours is very common. The immune system is working hard! Just ensure baby wakes for feeds.
Q: The injection site has a hard lump that won't go away. Is this concerning?
A: Small, painless lumps at injection site can last for weeks or even months. This is normal and will eventually disappear. Only worry if it's growing, painful, or red.
Q: Can I give baby a bath after vaccination?
A: Yes, you can bathe baby normally. Avoid vigorously rubbing the injection site.
Q: My older child has a cold. Should I delay baby's vaccination?
A: Mild illnesses like a cold don't usually require delaying vaccines. However, check with your pediatrician who can assess if your baby is well enough.
Q: The BCG site is forming a pus-filled boil. Is this an infection?
A: This is actually NORMAL for BCG! The vaccine causes a small lesion that may ulcerate and form a scar. This is expected and shows the vaccine is working. Don't apply any creams or try to pop it.
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Key Takeaways
Mild reactions are normal - Show the vaccine is working
Most symptoms last 1-3 days - Be patient
Comfort is key - Cuddles, breastfeeding, and rest help
Know the warning signs - High fever, seizures, difficulty breathing need immediate care
When in doubt, call your doctor - Trust your instincts
Vaccines save lives - These temporary discomforts protect from serious diseases
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This article was reviewed by pediatricians at Babynama. Last updated: January 2026
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