February 26, 2013

expert reaction to link between narcolepsy in children and swine flu vaccine

A study published in the BMJ found an increased risk of narcolepsy in children and adolescents who received the Pandemrix influenza vaccine during the 2009 pandemic in England. 

Prof Jonathan Ball, Professor of Molecular Virology at the University of Nottingham, said:

“This paper confirms a previous association between administration of a specific formulation of the swine flu pandemic vaccine and incidence of narcolepsy in children. It does not indicate why this association might exist and, as the authors point out, it is not clear whether these children would have gone on to develop this later anyway.

“The normal seasonal flu vaccine contains different ingredients and has proven to be very safe.  We mustn’t forget that flu can, in some vulnerable people especially the young and the old, be a very serious illness – so it is crucial that people continue to be vaccinated against seasonal flu.

“What the study does indicate is that further work is needed to assess the impact of these newer vaccine formulations, which were used because of a very specific need that arose due to the emergence of a new pandemic strain of the virus.”

Prof Adam Finn, Professor of Paediatrics at University of Bristol Medical School, said:

“It is now pretty clear that Pandemrix, an injected flu vaccine that was used in response to the swine flu pandemic that began in 2009, carried a risk of around one in 50,000 of narcolepsy when given to children, especially teenagers.   As well as causing suffering and distress to those affected and their families, this raises some important questions about why exactly this happened with this particular vaccine.

“The many children who received Pandemrix and are currently well are expected to remain fine as the problem, when it happens, seems to develop a few months after the vaccine and Pandemrix has not been in use for 2 years now.  Pandemrix is the only vaccine that has been linked to this problem – there is nothing to suggest that it occurs after other flu vaccines or vaccines against other diseases.”

Dr John McCauley, Director of the WHO Collaborating Centre for Influenza at the MRC National Institute for Medical Research, said:

“This is a very thoroughly carried piece of work on the association of narcolepsy with vaccination of children and young people with the pandemic swine influenza vaccine.  A few other countries have also detected this effect.  The increase in the rate of narcolepsy was about 14-fold increased.  This resulted in a case for about every 50,000 doses delivered.

“The current seasonal influenza vaccines are not the same as the swine influenza vaccine so the observed increase in narcolepsy is possibly a one-off event.  Surveillance needs to be continued.”

‘Risk of narcolepsy in children and young people receiving AS03 adjuvanted pandemic A/H1N1 2009 influenza vaccine: retrospective analysis’ by Elizabeth Miller et al.  published in BMJ on Tuesday 26^th February.