Immunization Reactions
Description / Symptoms
- You believe your child is having a reaction to an immunization
- Reactions to DTaP (Diphtheria, Tetanus, Pertussis), MMR (Measles, Mumps, Rubella), polio, Hemophilus influenzae type b, Hepatitis A, Hepatitis B, influenza, chickenpox (varicella), pneumococcal and meningococcal vaccines are covered
- Most local pain and swelling at the injection site occur within 2 days
- Fever with most vaccines begins within 24 hours and lasts 2 or 3 days
- With live vaccines (MMR and chickenpox), fever and systemic reactions usually begin between 1 and 4 weeks
- Severe allergic reactions are very rare, but can occur with any vaccine.
When to Call Your Doctor for Immunization Reactions
Call 911 Now If:
- Difficulty with breathing or swallowing
- Not moving or very weak
- Unresponsive or difficult to awaken
Call Your Doctor Now If:
- Your child looks or acts very sick
- Age < 12 weeks with fever > 100.4°F (38°C) rectally (Exception: occurs within 48 hours after DTaP shot)
- Fever > 105°F (40.6°C)
- High-pitched, unusual cry present > 1 hour
- Crying continuously for > 3 hours
- Redness or red streak around the injection site bigger than 1 inch
- Redness around the injection site persists > 48 hours (2 days)
Call Your Doctor Within 24 Hours If:
- You think your child needs to be seen
- Fever present > 3 days
- Measles vaccine rash (onset day 6 to 12) persists > 3 days
Call Your Doctor During Weekday Hours If:
- You have other questions or concerns
- Pain, tenderness, or swelling at the injection site persists > 3 days
- Fussiness from vaccine persists > 3 days
Home Care (Read "Call Your Doctor…" first):
Local reaction to the injection (all vaccines except oral polio):
Pain
For initial pain or tenderness at the injection site:
- Apply ice to the area for 20 minutes once
- Give acetaminophen (e.g. Tylenol) or ibuprofen by mouth
Fever
For fevers > 102°F (39°C), give acetaminophen (ok to use ibuprofen if > 6 months old).
General Reaction
All vaccines can cause mild fussiness, irritability and restless sleep. While this is usually due to a sore injection site, sometimes the cause is less clear. Some children sleep more than usual.
A decreased appetite and activity level are also common. These symptoms do not need any treatment and will usually resolve in 24-48 hours.
Call Your Doctor If:
- Fever lasts > 3 days
- Pain lasts > 3 days
- Injection site starts to look infected
- Your child becomes worse or develops any of the "Call Your Doctor…" symptoms
Chickenpox Vaccine
- Pain or swelling at the injection site for 1 to 2 days (in 19% of children)
- Fever lasting 1 to 3 days begins 17 to 28 days after the vaccine (in 14%)
Give acetaminophen (e.g. Tylenol) or ibuprofen for fever > 102°F (39°C). Never give aspirin for fever, pain or within 6 weeks of receiving the vaccine. (Reason: risk of Reye's syndrome — a rare but serious brain disease).
- Chickenpox-like vaccine rash (usually 2 lesions) at the injection site (in 3%)
- Chickenpox-like vaccine rash (usually 5 lesions) scattered over the body (in 4%)
- This mild rash begins 5 to 26 days after the vaccine and usually lasts a few days
- Children with these vaccine rashes can go to day care or school. (Reason: for practical purposes, vaccine rashes are not contagious)
- EXCEPTION: avoid school if widespread, weepy lesions. (Reason: probably actual chickenpox)
- Precaution: if vaccine rash contains fluid, cover it with clothing or Band-Aid
DTaP or DT Vaccine
The following harmless reactions to DTaP can occur:
- Pain, tenderness, swelling or redness at the injection site (in 25% of children) and lasts for 24 to 48 hours. Swollen arm or leg following 4th or 5th DTaP occur in 3% and is not serious
- Fever (in 25% of children) and lasts for 24 to 48 hours
- Mild drowsiness (30%), fretfulness (30%) or poor appetite (10%) and lasts for 24 to 48 hours
Hemophilus influenzae Type b (Hib) Vaccine
- No serious reactions reported
- Sore injection site or mild fever only occurs in 1.5% of children
Hepatitis A Vaccine
- No serious reactions reported
- Sore injection occurs in 20% of children, loss of appetite in 10%, and headache in 5%. Usually n%Fever
- If these symptoms occur, they begin 3-5 days after vaccine and last 1-2 days
Hepatitis B Virus Vaccine (HBV)
- No serious reactions reported
- Sore injection site occurs in 30% of children and mild fever in 3% of children
- Because fever from the vaccine is rare, any infant < 3 mo with a fever following the vaccine should be examined
Influenza Virus Vaccine
- Pain, tenderness or swelling at the injection site occurs within 6 to 8 hours in 10% of children
- Fever 101 to 103°F (38.4° to 39.5°C) occurs in 18% of children. Fevers mainly occur in young children
Measles Vaccine
- The measles vaccine can cause a fever (10% of children), and rash (5% of children) about 6 to 12 days following the injection
- The fever is usually between 101 and 103°F (38.4o and 39.5°C) and lasts 2 or 3 days
- The mild pink rash is mainly on the trunk and lasts 2 or 3 days
- No treatment is necessary. Your child is not contagious.
Call Your Doctor If:
- Rash becomes very itchy
- Rash changes to purple spots
- Rash lasts > 3 days
Meningococcal Vaccine
- No serious reactions
- Sore injection site for 1 to 2 days is uncommon
Mumps or Rubella Vaccine
There are no reactions except for an occasional sore injection site.
Pneumococcus Vaccine
- Pain, tenderness, swelling OR redness at the injection site in 15-30%
- Mild fever < 102%F (39°C) in 15% for 1-2 days
- No serious reactions
Polio Vaccine
There are no serious reactions to oral polio vaccine. Polio vaccine by injection occasionally causes some muscle soreness.
Related Health & Safety Information
Parent Care for Pediatric Symptoms. Copyright 2000-2006.