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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

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