Sunday, March 20, 2011

Adverse events following flu vaccination in Australia/ BMJ

Data suggest that children may have been hospitalized for post-swine flu vaccination seizures at a rate 2-6 times greater than their rate of hospitalization for swine flu disease.  Data are lacking on other post-vaccination side effects that might also occur. 

I suggest you read this short BMJ piece by authors Peter Collignan, Peter Doshi and Tom Jefferson in its entirety online.  Excerpts follow:
In Australia last year, one febrile convulsion occurred for every 100 to 200 young children vaccinated with CSL's influenza vaccine (2,3,4). Now in the US there have been similar concerns. A recent analysis of the American experience reported a rate of 60 seizures per 100,000 influenza vaccinations when given together with conjugated pneumococcal vaccine (5). However this is likely to under-estimate the true rate. One post-marketing vaccine safety study showed reports of febrile seizures admitted to hospital, was 5 times lower with passive surveillance (6)... in Australia's recent experience, 38% of children with febrile convulsions following vaccination (19 of 56) were admitted to hospital (4)...

In Australia in 2009, during winter when young children (0-4 years) were first hit with the new H1N1 strain, the admission rate for influenza was 57 per 100,000 (8). In the US, CDC says that influenza results in hospitalization for approximately 20 per 100,000 children aged 2 to 5 years (9), but vaccine-induced febrile convulsions resulting in hospitalization in US young children, likely occurred at a rate of 114 per 100,000 children vaccinated . According to the FDA, a "serious adverse event" is defined as hospitalization that results from a vaccine adverse event (10). Thus vaccinating young children without risk factors likely caused more serious adverse events than disease from the new "pandemic" itself.
There is poor safety data available for other serious adverse events that might occur in young children in addition to febrile seizures (11)...  In 2005, when a new study demonstrated that influenza vaccines were not saving elderly lives (16), many argued that this underscored the importance of vaccinating more children (17). Yet we have no evidence demonstrating that children are benefiting from this strategy but do have evidence that these vaccines are hospitalizing children...

No comments: