WHO statement on narcolepsy and Pandemrix vaccine

WHO Statement on Narcolepsy and Vaccination


8 February 2011

Since August 2010, following widespread use of vaccines against influenza (H1N1) 2009, cases of narcolepsy, especially in children and adolescents, have been reported from at least 12 countries. Narcolepsy is a rare sleep disorder that causes a person to fall asleep suddenly and unexpectedly. The rates reported from Sweden, Finland and Iceland have been notably higher than those from other countries. The National Institute for Health and Welfare of Finland issued a preliminary statement on 1 February 2011 following an investigation into the cases in Finland. A systematic retrospective registry-based review was conducted of all new narcolepsy cases diagnosed during 2006-2010 and cases in 2009-2010, born in 1990 or later, were reviewed using newly developed Brighton collaboration criteria for the disease. During 2009-2010 they found a higher risk of narcolepsy among those aged 4-19 years old who had received the vaccination against influenza (H1N1) 2009 compared with those who had not been vaccinated. The only pandemic vaccine used in Finland was Pandemrix, an adjuvanted influenza (H1N1) 2009 monovalent vaccine manufactured by GlaxoSmithKline. Pandemrix vaccine was used in 47 countries worldwide during the 2009-2010 season. Studies are ongoing to determine if the apparent increased risk of narcolepsy reported in Sweden is higher in vaccinated persons.

The National Institute in Finland (on the advice of the Finnish National Narcolepsy Task Force) has concluded that the risk of developing narcolepsy among those vaccinated aged between 4 and 19 years is about nine times greater than those unvaccinated in the same age group, corresponding to a risk of about 1 case of narcolepsy per 12,000 vaccinated in this age group. The increased risk has not been seen in younger or older age groups. Narcolepsy is a condition that has a strong genetic linkage, being almost uniquely seen in persons who have the (HLA) DQB1*0602 genotype. Of the cases of narcolepsy tested so far in Finland (n=22), diagnosed during 2009-2010, all have that genotype. The National Institute considers it probable that the Pandemrix vaccine was a contributing factor to this observed increase, and has called for further investigation of other co-factors that may be associated with the increased risk. . .

UPDATE:  In the US, an average of about 75 children/year die from flu-related causes.  Most of these children have underlying, chronic medical illnesses.  Usually about 15-20 child deaths/year occur in otherwise healthy children in the US.

There are over 50 million children in the US.  If half were vaccinated, and their rate of developing narcolepsy was the same as in Finland (one in 12,000), we might expect 2,000 new cases of narcolepsy in vaccinated children.  They would need a certain HLA type (a specific genetic predisposition).  But most people with that HLA type do not develop narcolepsy; in Finland narcolepsy appears to have been triggered by vaccination and possibly other unidentified exposures.

Narcolepsy is a serious medical condition, and in Finland, post-vaccination, it has been associated with other neurological problems including personality changes.  Narcolepsy may be deadly when someone with the disorder falls asleep at the wheel of a car.  

A risk benefit analysis might look something like this:  two thousand narcolepsy cases caused by flu vaccination versus 26 child deaths prevented. (This assumes that 50% of children were vaccinated and the vaccine was 70% effective.  These are reasonable assumptions for a year in which the vaccine is a good match to circulating flu strains.)  [75 child deaths x 50% vaccine uptake x 70% vaccine efficacy = 26 child deaths prevented.  I have not thrown in a factor for herd immunity since current vaccine uptake rates are not felt to lead to significant herd immunity for influenza.]

Granted, it is unclear what the risk of narcolepsy is for use of swine flu vaccine in the US; and it is unclear whether the novel Glaxo adjuvant used in Pandemrix swine flu vaccine outside the US may have contributed.  But I just did the math.  And it appears that if Finland has a similar childhood death rate from flu as the US, it could be seeing 80 cases of narcolepsy for every flu death prevented. 

These are serious numbers, and WHO, EMEA, CDC and other public health agencies must be terribly concerned about the findings and implications.