Vaccine Reactions – Is This Normal?

Vaccines are very safe.

They are not 100% safe though and they can have some side effects.

“Considering that the vaccines in the infant schedule are administered to millions of children each year, the list of known adverse events, even rare ones, is impressively short.”

O’Leary et al on Adverse Events Following Immunization: Will It Happen Again?

Fortunately, most of these side effects are harmless and don’t have any long term risks. And of course, the great benefits of vaccines outweigh those risks.

Common Vaccine Reactions

Although most kids don’t have any reactions at all, some do have mild reactions.

Among the possible vaccine reactions or side effects that can occur include:

• fussiness
• headache
• fever
• body aches
• redness or swelling at the injection site
• soreness or tenderness at the injection site
• tiredness
• poor appetite
• chills and sore joints
• rash
• diarrhea
• vomiting
• swelling of glands in the cheeks or neck

How commonly do they occur?

These side effects depend on the vaccine that was received and can range from 1 in 3 kids for some fussiness all the way down to 1 in 75 kids for kids who have swelling of their glands.

And they usually begin 1 to 3 days after the vaccine was given and last for 1 to 7 days.  Fortunately, fever and fussiness don’t last that long, typically going away after just a day or two.

Keep in mind that some reactions are more delayed though. This is especially true for the MMR vaccine, in which mild reactions, like a fever, rash, or swelling of glands might not occur until 6 to 14 days after a child got his vaccine.

What can you do if your child has a mild vaccine reaction?

Consult your health care provider, but keep in mind that treatment is often symptomatic, typically with a cold pack or cool cloth/compress for local reactions and pain reliever.

Fainting also commonly occurs after vaccines, especially in teens, but it is thought to be due to the vaccination process itself and not the vaccines. Still, it is something to be aware of.

What About More Moderate Reactions?

More moderate reactions after vaccines are fortunately more uncommon.

“There is low public tolerance of vaccine adverse reactions. Vaccines are therefore only licensed when the frequency of severe reactions is very rare and when only minor, self-limiting reactions are reported.”

WHO on Adverse events following immunization

Some of these moderate reactions might include:

• febrile seizures
• high fever
• persistent crying for 3 or more hours
• swelling of the entire arm or leg where the shot was given (especially after the 4th or 5th dose of DTaP)
• a temporary low platelet count (immune thrombocytopenic purpura or ITP)

Like the more common, mild reactions, these less common moderate reactions are also temporary and don’t usually have any lasting risks or consequences.

Then there are the more severe reactions, which thankfully are even more rare. These are the 1 in a million dose type reactions, such as life-threatening allergic reactions.

Of course, you should seek medical attention if you think that your child is having a more moderate or severe reaction to a vaccine.

And lastly, there are the so-called vaccine induced diseases, which are simply made up.

All of these reactions, as well as the risks of getting a natural infection, are listed in each vaccine’s VIS. The Vaccine Information Statements also includes information on how to report all possible vaccine side effects to VAERS.

What to Know About Common Vaccine Reactions

While most kids don’t have any reactions at all after their vaccines, those that do typically have mild reactions, including some fever, soreness, or swelling at the injection site. More moderate and severe reactions are rare.

More About Common Vaccine Reactions

• Vaccination site reaction or bacterial cellulitis?
• Should Your Child See a Doctor for these Immunization Reactions?
• Treatment of local injection reactions
• Medical Management of Vaccine Reactions in Children and Teens
• Editorial – Adverse Events Following Immunization: Will It Happen Again?
• Study – Risk of Recurrence of Adverse Events Following Immunization: A Systematic Review
• WHO – Adverse events following immunization
• What to do about vaccine side effects
• CDC – Possible Side-effects from Vaccines
• ACIP – Preventing and Managing Adverse Reactions
• Side Effects from Vaccines
• AAP – Vaccines and Side Effects: The Facts
• A look at the numbers in vaccine reactions
• A Serious Reaction After Vaccination Rarely Occurs Again With Later Immunization, Study Finds
• Ask the Experts: Vaccine Safety
• Side effects of childhood vaccines are extremely rare, new study finds
• Adverse skin reactions to vaccines
• Study – Severe reactions associated with diphtheria-tetanus-pertussis vaccine: detailed study of children with seizures, hypotonic-hyporesponsive episodes, high fevers, and persistent crying.
• Vaccine Side Effects and Adverse Events
• Study – The risk of immune thrombocytopenic purpura after vaccination in children and adolescents.