What to Look for After a Baby Gets His Shots

You might approach your child's well-baby visits with trepidation, worrying about the possible side effects from vaccinations 4. All vaccines have the potential to cause minor side effects 4. Knowing the symptoms associated with different vaccines and when they usually appear can help you prepare for the possibility by stocking up on appropriate medications. Having an idea of what to expect can also ward off frantic pediatrician calls in the middle of the night. According to the Centers for Disease Control and Prevention, studies have not proven a connection between vaccines and autism in children.


Fever is one of the most common side effects of immunizations in babies. Most fevers begin within 24 hours and last two to three days, Seattle Children's Hospital reports 1. However, fever starts later with live vaccines. In chicken pox vaccine, fever could start 17 to 28 days after vaccination, and fever may follow measles vaccination six to 12 days after injection. If your baby is under 12 weeks old, report any fever over 100.4 degrees Fahrenheit rectally to his pediatrician. If an older infant has a fever of 104 degrees that doesn't improve within two hours after giving an antipyretic such as acetaminophen or ibuprofen, call the doctor. Also call if his fever persists more than three days or returns after resolving. Don't give an infant aspirin, not even baby aspirin.

Behavioral Changes

Getting jabbed with a needle and experiencing a fever and sore arm (or leg) makes many babies irritable. But if your baby cries inconsolably for more than three hours or has a high-pitched, unusual cry, let his pediatrician know. Sleeping less than usual, restless sleep or drowsiness can also occur as side effects of vaccination.

Muscle Aches

Your baby can experience pain both at the injection site and overall achiness after a vaccination. The polio vaccine can cause muscles aches, and the meningococcal vaccine can cause joint pain. Applying a cold pack to the injection site for 20 minutes can help decrease pain and swelling at the site. The DTaP (diphtheria, tetanus and pertussis) vaccine site develops a large swelling after the fourth or fifth injection in around 5 percent of children, but most can still move the arm or leg normally, according to Seattle Children's Hospital 13.

Skin Reactions

Only a few vaccines cause skin rashes, including the chicken pox and measles vaccines. The chicken pox rash normally occurs near the injection site and consists of two to five chicken-pox-like lesions that last several days. The measles rash consists of pink spots that develop on the trunk and last two to three days. Redness and swelling occur commonly at the injection site. Red streaks radiating out from the injection site could indicate an infection at the site, according to Seattle Children's Hospital 1. Hives that appear can indicate an allergic reaction to some ingredient in the injection, rather than a reaction common to the vaccine.

Serious Reactions

Serious reactions to vaccines include anaphylaxis from an allergic reaction or seizures. Around one of every 600,000 people who gets the hepatitis B vaccine has an anaphylactic reaction, The Children's Hospital of Philadelphia reports, although no one has died from the vaccine 3. In rare cases -- less than one case per million in the United States, according to the Centers for Disease Control and Prevention -- the measles, mumps, rubella vaccine (MMR) causes a temporary low platelet count. Low platelets can cause unexplained bleeding or bruising.