Allergic Reactions to a Baby Vaccination

Babies receive numerous vaccinations during their first four months of life. While these injections make children cry (and often make parents squeamish), the practice has nearly erased many childhood diseases that were once considered deadly.

A baby receives a vaccination
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Despite myths and misconceptions about their "dangers," immunizations are nothing less than essential to keeping your child healthy and out of harm's way. However, vaccinations can have some side effects.

Knowing which ones are normal and which are not can help you decide when to take action in the unlikely event your child has an adverse reaction.

Common Side Effects

It is not unusual for babies to have side effects after getting a vaccination. Most are not all that serious and usually resolve within a day or two. The most common include:

  • Tenderness, redness, or swelling at the injection site
  • A slight fever
  • Irritability
  • Crying

Breastfeeding or bottle-feeding after an injection may help calm a fussy baby.

Signs of a Serious Reaction

While rare, serious allergic reactions to infant vaccines have been known to occur. If not treated immediately, it could lead to a potentially life-threatening allergic reaction known as anaphylaxis. Over the course of minutes to hours, the symptoms can worsen as the airways become increasingly constricted, leading to respiratory distress and other serious side effects.

When to Call 911

Call 911 if your baby experiences some or all of the following symptoms after an immunization:

Most cases of anaphylaxis occur within eight hours of getting a shot but can happen in less than 30 minutes. If left untreated, anaphylaxis can lead to unconsciousness, seizures, shock, coma, and even death.

Estimating Risk

Anaphylaxis can occur in response to any medication. While the possibility is worrisome, it should not cause you to avoid vaccinating your child. Research has shown that the risk is extremely low.

A 2016 study from the Centers for Disease Control and Prevention (CDC) reviewed data from the Vaccine Safety Datalink and confirmed that there were just 33 cases of anaphylaxis out of 25,173,965 vaccine doses administered from January 2009 to December 2011.

Based on their findings, the CDC researchers concluded that the risk of vaccine-triggered anaphylaxis is rare for all age groups.

When to Postpone or Avoid a Vaccination

As a general rule, infant immunizations are safe and a vital component of your child's good health. There are certain circumstances in which it may be necessary to skip or delay a shot, however:

  • If an infant has a fever, they shouldn't receive a vaccination until they're completely recovered. It is safe to vaccinate a child with a cold, however.
  • If an infant has had a previous allergic response to a vaccine, it's important to seek expert consultation with an allergist to identify the cause. This can help determine which vaccines are safe or unsafe for use.

Any infant with fever or illness should be evaluated by the doctor before receiving any vaccine.

Vaccines Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Mom and Baby
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2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. McNeill MM, Weintraub ES, Duffy J. Risk of anaphylaxis after vaccination in children and adults. J Allergy Clin Immunol. 2016 Mar;137(3):868–78. doi:10.1016/j.jaci.2015.07.048

  2. Centers for Disease Control and Prevention. Vaccine recommendations and guidelines of the ACIP: Preventing and managing adverse reactions. Updated July 16, 2013.