Do you know how to recognize a vaccine reaction?

Like with prescription drugs and other pharmaceutical products, reactions to vaccines can be mild or severe. There can be complete recovery or long lasting health problems after vaccine reactions. Rarely, vaccine reactions can be fatal. 1 2

If you are making a decision about vaccination for yourself or your child, it is important to first become fully informed about each vaccine’s reported side effects, precautions and contraindications, which means reasons for why a person may be at risk for having a serious reaction. 3 4

It is especially important for parents to become informed about vaccine complications and how to recognize the symptoms of a vaccine reaction. 5

When a person collapses within seconds, minutes or hours of vaccination, it may be anaphylactic shock – a life threatening allergic reaction like can happen after bee stings, or exposure to certain drugs, chemicals or foods like peanuts. 6 7

Signs of anaphylaxis include problems with breathing and swallowing, wheezing, chest or abdominal pain, vomiting, diarrhea, hives and rashes, swelling, weakness, mental confusion and loss of consciousness.

Depending upon the vaccine, most vaccine reactions take longer than a few minutes to develop. For example, brain inflammation reactions to pertussis (whooping cough) vaccine in the DPT or DTaP shots usually occur within 72 hours or a week of vaccination, 8 while it may take between one and two weeks for signs of brain inflammation to develop after getting live virus measles, mumps and rubella vaccine. 9

There should be careful monitoring of signs and symptoms of vaccine reactions for at least a week or two after vaccination. Look for symptoms like:

• High fever (over 103F);

• Skin redness or discoloration, swelling or hardened lump and pain at the site of the injection; 10 11 12

• High pitched screaming, which is shrill inconsolable crying by babies that lasts for hours 13 14
• Collapse/Shock, which is known as a hypotonic/hyporesponsive episode, when a child suddenly goes limp and may have pale skin or blue tinged lips 15

• Excessive sleepiness, when a child sleeps deeply for an unusually long period of time and does not wake to eat

• Convulsion, also known as a seizure, which may include rolling of eyes, blank staring for long periods, twitching, trembling, shaking, stiffness and jerking of the body 16 17 18 19 20

• Brain inflammation, also known as encephalitis or encephalopathy, is the most serious vaccine complication. Depending upon the age, symptoms can include agitation, high-pitched screaming with arching of the back or inconsolable crying, convulsions, muscle weakness, paralysis, double vision, slurred speech, mental confusion and unconsciousness. 21 22 23 24 25 26 27

• Behavior Changes and Mental or Physical Regression after vaccination can be signs of brain or immune system damage, such as loss of muscle control and developmental milestones, sleep disturbances, personality changes, onset of severe allergies and intestinal disorders or other dramatic changes in health. 28 29 30 31 32 33 34

If there is a question about whether or not brain inflammation or another type of serious reaction is occurring after vaccination, contact the person who administered the vaccine(s) and go to a hospital emergency room immediately.

The details of the health problems experienced after vaccination should be entered into the permanent medical record and reported to the federal Vaccine Adverse Event Reporting System. 35

If a doctor or medical worker will not make a vaccine reaction report to the government, you can make a report yourself. 36

At NVIC.org, learn more about vaccines, diseases and the human right to informed consent to medical risk taking.

Empower yourself today with well-referenced information that can help you make educated decisions about vaccination.

It’s your health. Your family. Your choice.