Pertussis vaccine does not affect encephalopathy outcome

January 01, 0001

Pertussis vaccine does not affect encephalopathy outcome

Pertussis vaccination has been alleged to cause an encephalopathy that involves seizures and subsequent intellectual disability. In a previous retrospective study, 11 of 14 patients with so-called vaccine encephalopathy had Dravet syndrome that was associated with de-novo mutations of the sodium channel gene SCN1A. In this study, the researchers from Australia aimed to establish whether the apparent association of Dravet syndrome with vaccination was caused by recall bias and, if not, whether vaccination affected the onset or outcome of the disorder. Dates of vaccination and seizure onset were available from source records for 40 patients. Patients who had seizure onset on the day of or the day after vaccination (n=12) were included in the vaccination-proximate group and those who had seizure onset 2 days or more after vaccination (n=25) or before vaccination (n=3) were included in the vaccination- distant group.

There were no differences in intellectual outcome, subsequent seizure type, or mutation type between the two groups. Furthermore, in a post-hoc analysis, intellectual outcome did not differ between patients who received vaccinations after seizure onset and those who did not.

The researchers concluded: "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."

This is reassuring.

For the full abstract, click here.

The Lancet Neurology 9(6):592-598, June 2010
© Elsevier Ltd 2010
Effects of vaccination on onset and outcome of Dravet syndrome: a retrospective study. Anne M McIntosh, Jacinta McMahon, Leanne M Dibbens et al. Correspondence to Samuel Berkovic:

Category: B. Blood/Blood Forming Organs/Immune Mechanisms. Keywords: effects, vaccination, onset, outcome, Dravet syndrome, retrospective study, journal watch.
Synopsis edited by Dr Stephen Wilkinson, Melbourne, Australia. Posted on Global Family Doctor 15 June 2010

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