Flu jab link to brain disorder cases

[Posted: Thu 19/04/2012 by Niall Hunter, Editor www.irishhealth.com]

A new Irish report has found that there is a significant 13-fold higher risk of the brain disorder narcolepsy in those who received the vaccine Pandemrix during the 2009-10 swine flu pandemic.

A total of 28 cases of narcolepsy with a symptom onset since April 2009 in children and adolescents aged five to 19 were identified in the report.

It found 22 of these 28 children and adolescents had received Pandemrix before the onset of narcolepsy symptoms.

Of 30 narcolepsy cases in children and adults with symptom onset from April 2009 who had had pandemic flu vaccine, 25 had received a pandemic vaccine before the first onset of narcolepsy symptoms, and 24 of these received Pandemrix.

Five cases had received the vaccine after the first symptom onset and were considered unvaccinated for the purposes of the review.

The review, carried out by the Health Protection Surveillance Centre (HPSC) at the request of the Department of Health and the HSE, found that there was a significant 13-fold higher risk of narcolepsy in vaccinated compared to unvaccinated people.

The Department of Health said the results were very similar to those reported in 2010 in Sweden and Finland, with a clear increased risk evident from the available Irish data. It is believed that more cases of narcolepsy possibly linked with the vaccine may be confirmed.

However, the Department said international experts agreed that a number of factors were likely to have led to the increased risk of narcolepsy associated with the vaccine, and a number of international studies werecontinuing which should provide additional information.

The review looked at possible cases of narcolepsy linked with the administration of the Pandemrix jab during the 2009-10 flu pandemic.

It found that the average delay between getting the Pandemrix jab and the first symptom of narcolepsy was 2.02 months.

Narcolepsy is a neurological disorder caused by the brain's inability to regulate sleep/wake cycles normally. There is no cure, and the symptoms can include excessive daytime sleepiness, cataplexy (sudden loss of muscular/postural tone), vivid hallucinations during sleep or after wakening, and brief episodes of total paralysis at the beginning or end of sleep.

The Department of Health said it was working with the HSE and the Department of Education to put in place necessary supports for those people affected by this condition. There is particular concern about the effects of narcolepsy on the academic performance of schoolchildren.

Department Chief Medical Officer Dr Tony Holohan stressed the importance of vaccination for protecting people's health.

He said vaccination was very safe and it was important that the current vaccination programmes continued to protect children and adults against the serious consequences caused by preventable diseases.

"People can continue to have a high level of confidence in our vaccination programmes."

The European Medicines Agency (EMA), following a review last year, concluded that the overall benefit-risk balance of Pandemrix remained positive.

The EMA has also suggested that the flu jab may interact with genetic or environmental factors which might increase the risk of narcolepsy in those receiving it, and other factors too may have contributed to the link between the vaccine and narcolepsy.

A genetic factor which can predispose people to developing narcolepsy is found in around 28% of the Finnish population. In Northern European populations, this genetic risk for the condition can be found in around 25% to 28% of the populaiton, the HPSC report says.

Pandemrix is no longer recommended for use in Ireland. This year’s flu jab does not contain Pandemrix.