Tag: diphtheria

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

Diphtheria in Canada

A lot of people were surprised by the news of a case of diphtheria in Canada this past week.

Some folks were quick to blame the anti-vaccine movement, assuming it was in an unvaccinated child.

News soon came that the child was vaccinated!

“I’ve always been on top of that, I’m a firm believer in immunizations.”

Mother of 10-year-old with diphtheria

What happened next?

Anti-vaccine folks began using the fact that he was vaccinated, but still developed diphtheria, as some kind of proof that vaccines don’t work.

The Case of Diphtheria in Canada

They are wrong.

The diphtheria vaccines have worked very well to control and eliminate diphtheria from Canada, just like it has in the United States.

Diphtheria has become rare since the pre-vaccine era.
Diphtheria has become rare since the pre-vaccine era.

So how did a vaccinated child in Canada get diphtheria?

It’s simple.

He has cutaneous diphtheria, not respiratory diphtheria.

What’s the difference?

“Extensive membrane production and organ damage are caused by local and systemic actions of a potent exotoxin produced by toxigenic strains of C. diphtheriae. A cutaneous form of diphtheria commonly occurs in warmer climates or tropical countries.”

Vaccines Seventh Edition

Cutaneous diphtheria occurs on your skin. It is usually caused by non-toxigenic strains of Corynebacterium diphtheriae.

On the other hand, respiratory diphtheria is usually caused by toxigenic strains of Corynebacterium diphtheriae.

Diphtheria strikes unprotected children.The diphtheria vaccine (the ‘D’ in DTaP and Tdap), a toxoid vaccine, covers toxigenic strains. More specifically, it covers the toxin that is produced by toxigenic strains of Corynebacterium diphtheriae. It is this toxin that produces the pseudomembrane that is characteristic of diphtheria.

It was the formation of this pseudomembrane in a child’s airway that gave diphtheria the nickname of the “strangling angel.”

So why the fuss over this case in Canada? They likely don’t yet know if it is a toxigenic strain. If it is, then it could be a source of respiratory diphtheria.

But remember, even if these kids developed an infection with the toxigenic strain of Corynebacterium diphtheriae, those that are fully vaccinated likely wouldn’t develop respiratory diphtheria. Again, it is the toxin that the bacteria produces that cause the symptoms of diphtheria. The vaccine protects against that toxin.

For example, when an intentionally unvaccinated 6-year-old in Spain was hospitalized with severe diphtheria symptoms a few years ago, although many of his friends also got infected, non of them actually developed symptoms because they were all vaccinated.

Diphtheria Is Still Around

Diphtheria is DeadlyTragically though, especially since diphtheria is still endemic in many countries, we are starting to see occasional lethal cases of diphtheria in many more countries where it was previously under control:

  • at least 7 diphtheria deaths in Venezuela this past year
  • a family that became infected in South Africa in which at least one child died (August 2017)
  • an unvaccinated 3-year-old who died in Belgium (2016)
  • a 22-year-old unvaccinated women who died in Australia (2011)

It is even more tragic that diphtheria is not under control in so many more countries.

In 2016, the WHO reported that there were just over 7,000 cases of diphtheria worldwide. While that is down from the 30,000 cases and 3,000 deaths in 2000, thanks to improved vaccination rates, there is still work to be done.

And as this recent case in Canada shows, diphtheria is still around in many more places than we would like to imagine.

Get educated. Vaccines are necessary.

What to Know About Diphtheria in Canada

The case of cutaneous diphtheria in Canada is a good reminder that vaccines are still necessary.

More on Diphtheria in Canada