Last updated on November 4th, 2015 at 01:18 pm
There is really only one reason to vaccinate – protecting everyone, especially children, from dangerous vaccine preventable diseases. We have eliminated smallpox. We have almost eliminated polio.
And we had almost made measles extinct, until the myth that the MMR vaccine (to prevent mumps, measles and rubella) caused autism, started by one of sciences greatest fraudsters, the defrocked Mr. Andy Wakefield. It’s a myth that’s been thoroughly and definitively debunked.
One vaccine preventable infectious disease that we’ve been unable to conquer is whooping cough (caused by the bacteria, Bordetella pertussis), also known as pertussis. Pertussis is a relatively dangerous infection, the disease itself has serious consequences for children and adults:
- 1 in 4 (23%) get pneumonia (lung infection)
- 1 or 2 in 100 (1.6%) will have convulsions (violent, uncontrolled shaking)
- Two thirds (67%) will have apnea (slowed or stopped breathing)
- 1 in 300 (0.4%) will have encephalopathy (disease of the brain)
- 1 or 2 in 100 (1.6%) will die
Whooping cough can be easily prevented by the DTaP or Tdap vaccines (which also protect against tetanus and diphtheria). The vaccines can be given to infants as early as 6 weeks to 2 months old.
As with all medical procedures, there are some adverse effects with the pertussis vaccines. Moderate adverse effects from the vaccine occur in about 1 in 10,000 (or even fewer) injections. The most severe effects, which may or may not be causally related to the vaccine since the rate is so low, are in the range of 1 out of a million doses.
One out of one million doses of the vaccine cause a serious adverse event (maybe). Compare that to the 1-2 out of 100 will die of the disease. Unless you flunk math, there is no rational reason to avoid the vaccine.
Pertussis and epilepsy are linked
But there’s more. A new study published in JAMA describe evidence that pertussis infections is linked to some forms of epilepsy, a group of neurological diseases that is characterized with seizures, some of them violent. Epilepsy is a difficult disease to manage, although many medications have been useful in keep the seizures under control. The complications of epilepsy are numerous, including learning disabilities, brain damage, and strokes.
The cohort study examined medical registries covering all Danish hospitals to identify a cohort of all patients with pertussis born between 1978 and 2011. The researchers then identified 10 individuals from the general population for each pertussis patient, matching individuals with same sex and year of birth.
Denmark is often used for epidemiological studies, because there is a national database of health care records for all residents that allow for highly specialized sorting and searching of the data.
The researchers identified 4700 patients with pertussis (48%male), of whom 90 developed epilepsy. They determined that the incidence rate for epilepsy at age 10 years was 1.7% for patients with pertussis, and 0.9% for the matched population cohort from the general population.
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From that data, the researchers determined that the hazard ratio was 1.7, or that there was a 1.7X greater risk for epilepsy after a pertussis infection than there is for the general population. Admittedly, the absolute risk is fairly low, 1.7% chance of epilepsy after contracting pertussis, but it is still clinically significant, as compared to the general population.
From a personal point-of-view, that’s a risk worth eliminating, especially in light of the other risks of a pertussis infection, up to and including death. The risks of a lifetime of epilepsy, a serious, non-trivial neurological disease, far exceeds the real and imagined risks associated with the pertussis vaccines.
Yes, the current pertussis vaccine isn’t perfect with respect to effectiveness (part of the reason lies with previous antivaccination efforts, which overstated some issues with the older, better vaccine). But as opposed the crazy math of the vaccine deniers, that is, anything less than 100% effectiveness is approximately equal to 0% effectiveness, the pertussis vaccines are incredibly useful at preventing or reducing the risk of whooping cough.
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For example, in many studies of pertussis epidemics recently, unvaccinated and under-vaccinated children are up to 25X more likely to contract pertussis as fully vaccinated children. Which means, according to the epilepsy study, a substantially higher risk of getting epilepsy.
Getting the whooping cough vaccine is the right thing to do.
Key citations
- Olsen M, Thygesen SK, Østergaard JR, Nielsen H, Henderson VW, Ehrenstein V, Nørgaard M, Sørensen HT. Hospital-Diagnosed Pertussis Infection in Children and Long-term Risk of Epilepsy. JAMA. 2015 Nov 3;314(17):1844-1849. doi: 10.1001/jama.2015.13971. PubMed PMID: 26529162.
