A case study released this week looks at 5 children who were considered to have vaccine encephalopathy caused by pertussis vaccinations. In this case study, all five children were found to have Dravet Syndrome, a genetic condition involving how the brain uses sodium.
The phrasing of “alleged cases” will likely draw some critique. Parents are very sensitive to the accusation that they didn’t see what happened, in this case seizures and regression following vaccination. Alleged in this case doesn’t challenge what the parents saw, but what it means. It appears that individuals with Dravert syndrome don’t get through childhood without regression (there don’t appear to be cases with the mutation and no syndrome in adults). In the words of the vaccine court, these individuals would have Dravert’s syndrome in any event, making it impossible to show that vaccines are the causation in fact.
Dr. Vincent Ianelli reports over at pediatrics.about.com that the cases include:
14-year-old mentally retarded boy with autistic features, who was a healthy infant until he got his vaccines when he was 7 months old
20-year-old with delayed development and autistic-like features who began having seizures right after getting vaccines at 2 months
2-year-old with a mild expressive speech delay who developed seizures after getting vaccines at age 4 months
4-year-old with “slowing development” who began having seizures after the six month vaccines
3-year-old regressed development and autistic-like features who began having seizures after getting vaccines at age 4 months
In these five case, genetic testing resulted in a diagnosis of Dravet Syndrome.
From Dr. Ianelli:
Dravet syndrome is a rare, genetic cause of encephalopathy that causes seizures that are hard to control and developmental delays.
Since fever is the usual trigger of the first seizure and subsequent seizures, it is important that children with Dravet syndrome get all of their vaccines, since natural infections will cause more fever and put them at risk for more seizures. In another study, “A retrospective study of the relation between vaccination and occurrence of seizures in Dravet syndrome,” only 16% of patients with Dravet syndrome had a vaccine related seizure as their first manifestation.
The researchers also state “that although vaccination might trigger an earlier onset of the presenting symptoms of Dravet syndrome, there is no evidence that the outcomes, in terms of subsequent seizure types or intellect, are any different between those patients with Dravet syndrome whose symptoms started within 2 days of vaccination and those whose symptom onset was not related temporally to vaccination.”
Dravet syndrome is a rare epileptic encephalopathy linked to mutations in SCN1A (neuronal sodium channel ?1 subunit) and characterized by an onset in infancy with polymorphous seizure types and developmental decline. It was reported recently that a proportion of patients previously diagnosed with alleged vaccine encephalopathy might possess SCN1A mutations and clinical histories that enabled a diagnosis of Dravet syndrome, but these results have not been replicated. We present here the cases of 5 children who presented for epilepsy care with presumed parental diagnoses of alleged vaccine encephalopathy caused by pertussis vaccinations in infancy. Their conditions were all rediagnosed years later, with the support of genetic testing, as Dravet syndrome. We hope that these cases will raise awareness of Dravet syndrome among health care providers who care for children and adolescents and aid in earlier recognition and diagnosis.
This isn’t the first work linking alleged vaccine encephalopathy with Dravet syndrome in some cases. Last year a study in The Lancet, Effects of vaccination on onset and outcome of Dravet syndrome: a retrospective study (also summarized in Pertussis Vaccination Triggers Dravet Syndrome in Predisposed Children) came to the conclusion:
Vaccination might trigger earlier onset of Dravet syndrome in children who, because of an SCN1A mutation, are destined to develop the disease. However, vaccination should not be withheld from children with SCN1A mutations because we found no evidence that vaccinations before or after disease onset affect outcome.
The anchor author on that study has a previous study, De-novo mutations of the sodium channel gene SCN1A in alleged vaccine encephalopathy: a retrospective study. They found 11 of 14 patients with alleged vaccine encephalopathy had Dravet syndrome (SMEI). Here is the abstract:
Vaccination, particularly for pertussis, has been implicated as a direct cause of an encephalopathy with refractory seizures and intellectual impairment. We postulated that cases of so-called vaccine encephalopathy could have mutations in the neuronal sodium channel alpha1 subunit gene (SCN1A) because of a clinical resemblance to severe myoclonic epilepsy of infancy (SMEI) for which such mutations have been identified.
We retrospectively studied 14 patients with alleged vaccine encephalopathy in whom the first seizure occurred within 72 h of vaccination. We reviewed the relation to vaccination from source records and assessed the specific epilepsy phenotype. Mutations in SCN1A were identified by PCR amplification and denaturing high performance liquid chromatography analysis, with subsequent sequencing. Parental DNA was examined to ascertain the origin of the mutation.
SCN1A mutations were identified in 11 of 14 patients with alleged vaccine encephalopathy; a diagnosis of a specific epilepsy syndrome was made in all 14 cases. Five mutations predicted truncation of the protein and six were missense in conserved regions of the molecule. In all nine cases where parental DNA was available the mutations arose de novo. Clinical-molecular correlation showed mutations in eight of eight cases with phenotypes of SMEI, in three of four cases with borderline SMEI, but not in two cases with Lennox-Gastaut syndrome.
Cases of alleged vaccine encephalopathy could in fact be a genetically determined epileptic encephalopathy that arose de novo. These findings have important clinical implications for diagnosis and management of encephalopathy and, if confirmed in other cohorts, major societal implications for the general acceptance of vaccination.
A recent study out of Germany took a bit more cautious interpretation: A retrospective study of the relation between vaccination and occurrence of seizures in Dravet syndrome. But the abstract does not address the question of whether outcome depends upon whether the first seizure is possibly vaccine related or not.