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The Cause Behind Seizures post-Vaccination


The anti-vaccination movement is a dangerous one. Children are falling ill (and in certain cases dying) over nothing more than fear and misinformation. The problem is science doesn’t have all the answers and it is tempting to look to someone — or in this case a group of someones– who claim to have those answers, true or not. Well science eventually gets the answers we need and now scientists have found genetic clues to explain why a small number of children have febrile seizures—brief convulsions—after receiving the measles, mumps and rubella (MMR) vaccine.

First of all, they stressed there was no need to scrap the MMR vaccine—which was caught in a health scare in 1998 that watchdogs later declared groundless—and described its use as a “great achievement” in saving lives. The team found that febrile seizures occurred in roughly one in every 1,000 children who were given the MMR vaccine.

Two genetic variants came to light that pointed to a higher risk of a febrile seizure in the second week following MMR vaccination They lie on genes that play an important role in how the immune system reacts to viral intruders

Febrile seizures for those who didn’t click the link are the term for when a child develops a high temperature, loses consciousness and spasms. They typically will have no long lasting consequences and typically occur in the first 24 hours of an illness. Tt may not occur when the fever is highest and simple things like ear infections, a cold or viral illness may trigger a febrile seizure. A genetic link is not surprising since they typically run in families and are typically more frightening than severe. The episode usually lasts for a minute or two, but apart from causing alarm for parents and the need for a checkup afterwards, is typically not dangerous.

A known but very rare side effect of vaccination or viral infection, febrile seizures are different from epileptic seizures in that they occur without fever. In addition, four other variants were found that link to febrile seizures in general, which we should note have no connection with the MMR vaccine.

These four lie on genes that help to govern ion channels, an essential communications link between nerve cells. Children who had the highest tally of the four variants were almost four times likelier to have febrile seizures than counterparts with the least number.

The six variants are unlikely to account for more than just a small proportion of the genetic causes for seizures, the researchers said.

Further work should tease out other genetic culprits, hopefully leading to a diagnostic test to show which children could be at greater risk of a febrile seizure after a jab. The study was unable to say whether children who had seizures did so as a result of getting a triple immunisation, as opposed to getting single shots to protect against the three diseases. The triple vaccine is the only available in Denmark, where the study took place.

In addition, the gene trawl was only carried out in Denmark, and it is unknown whether the same risk exists, or exists to the same degree, in children elsewhere. However, the research should throw up new pathways for exploring febrile seizures.

“The MMR vaccine is a great public health success, estimated to prevent the death of more than one million children worldwide per year,” Lead scientist Bjarke Feenstra said.

As far as the MMR vaccine is concerned, it could improve an already good and safe vaccine, he said.

“The knowledge gained from studies like ours may ultimately lead to even safer vaccines.”

In 1998, a study published in the British journal The Lancet unleashed a scare that the triple vaccine caused autism.

Even though the allegation was scientifically debunked and the study was later withdrawn, fears about the MMR vaccine persisted, prompting some parents to refuse immunisation for their child.

That in turn reduced “herd immunity”—the protection that comes when everyone is vaccinated—and placed non-immunised children at risk. Outbreaks of different vaccine preventable diseases have popped up over the last few years because of this fear.

The bottom line, as always, is that vaccines are safe. There is no cause for alarm and in the rare cases where vaccines do cause problems, like the one above, the cause gets parsed out instead of blindly blaming it on vaccines. Get your children vaccinated, it can save their life, or at the least, reduce suffering from some preventable and horrible illness.

There is no controversy, anymore than there is a controversy between people who say the earth is round and those who think it is flat. Vaccines are safe, it has been proven time and time again.

Please vaccinate your children or at least read actual peer-reviewed research on the subject and come to your own conclusions. Google scholar will help in a lot of cases point you in the right direction if you do not know where to start or how to find peer-reviewed works.

Bjarke Feenstra et al. (2014). Common variants associated with general and MMR vaccine–related febrile seizures Nature Genetics : dx.doi.org/10.1038/ng.3129

One response

  1. Pingback: ScienceSeeker Editor’s Selections October 26 – November 1, 2014 |

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