Tag: fainting

What Are Hypotonic-Hyporesponsive Episodes?

Just about any side effect after a vaccine can be scary for parents.

What if your child suddenly became limp, wasn’t responsive, and was pale?

That would be scary for any parent.

What Are Hypotonic-Hyporesponsive Episodes?

But that’s just what can happen when a child has a hypotonic–hyporesponsive episode (HHE).

“A hypotonic-hyporesponsive episode (HHE) is the sudden onset of hypotonia, hyporesponsiveness, and pallor or cyanosis that occurs within 48 hours after childhood immunizations.”

DuVernoy et al on Hypotonic-hyporesponsive episodes reported to the Vaccine Adverse Event Reporting System (VAERS), 1996-1998

These types of episodes were once thought to happen once for every 1,750 DTP vaccines given.

HHE is much more rare since we switched to a new pertussis vaccine.
HHE is much rarer since we switched to a new pertussis vaccine.

Fortunately, although they certainly do sound scary, the episodes stop on their own and  don’t cause any permanent harm.

Hypotonic-hyporesponsive episodes were even removed as table injuries after DTP back in 1995. It is not that HHE can’t occur after DTP, DTaP, or other vaccines, but rather that HHE doesn’t then cause any permanent neurological damage to the child.

And it is rare for kids to have a second episode, so they can continue to get vaccinated. HHE is not a good reason to skip or delay all of your child’s vaccines. While not a contraindication to getting vaccinated, having an episode of HHE “within 48 hours after receiving a previous dose of DTP/DTaP,” is listed as a precaution to getting another dose of DTaP or Tdap though.

“In general, vaccinations should be deferred when a precaution is present. However, a vaccination might be indicated in the presence of a precaution if the benefit of protection from the vaccine outweighs the risk for an adverse reaction.”

CDC on Vaccine Contraindications and Precautions

Also, HHE has become even more rare since we switched to using DTaP, instead of the older DTP vaccine. So being worried about HHE is definitely not a good reason to skip or delay any vaccines.

What to Know About Hypotonic-Hyporesponsive Episodes

Hypotonic-hyporesponsive episodes were more common after the older DTP vaccines, but still didn’t cause any long term problems and aren’t a good reason to skip or delay your child’s vaccines.

More About Hypotonic-Hyporesponsive Episodes

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?

In this 2011 report, the IOM concluded that few health problems are caused by or clearly associated with vaccines.
In this 2011 report, the IOM concluded that “few health problems are caused by or clearly associated with vaccines.”

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 (idiopathic 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