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|The MedAlerts Blog|
This year, Americans will be offered a Flu shot that has a combination of three different strains: Influenza B, H3N2 ("Hong Kong"), and the 2009 H1N1. But some countries are banning H1N1.
This month I will look at two countries that have banned H1N1 and see whether their reason for doing this is true here in the United States.
Finland has banned H1N1 because of an alarming rise in the number of narcolepsy cases (they had 15 cases following H1N1 flu injections).
Have narcolepsy rates associated with Flu shots changed in the United States?
To answer this question, we must define "narcolepsy" so that it can be found in MedAlerts searches. As usual, we will consult the MedDRA classification of symptoms. It shows narcolepsy in two different places:
|Top-level term||Next-level term||Mid-level term|
|Nervous system disorders||Sleep disturbances||Narcolepsy and hypersomnia|
|Psychiatric disorders||Sleep disorders and disturbances||Narcolepsy and associated conditions|
So we will do this MedAlerts search:
Here is the graph:
But this graph combines Seasonal Flu and H1N1, so how do we know whether H1N1 is responsible for the spike? If you separate the 60 events in the 2009-2010 season, 26 are from Seasonal Flu and 34 are from H1N1. So although Seasonal Flu was associated with a large number of narcolepsy cases, H1N1 was found in even more of these events.
It appears that Finland's experience with the Flu vaccine is also happening here in the United States.
Australia has banned H1N1 because of 23 convulsion cases (mostly in children).
The MedDRA places convulsions here:
|Nervous system disorders Seizures (incl subtypes)||(top-level term) (next-level term)|
So we will do this search:
Let's look in detail at the 2009-2010 season to see if children are more strongly affected (as Australia claims). Here is a graph of H1N1 flu associated with convulsions, broken down into three age groups: under 5 years old, 5 to 10 years old, and over 10 years old (these are the cut points for policy recommendations):
So as with Finland, it seems that Australia's experience with the flu vaccine is also happening here in the United States.
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