Published: February 2010
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Seasonal flu vaccine - summary of spontaneous reporting in New Zealand
Prescriber Update 31(1): 3
February 2010
With the advent of the pandemic flu last year, there has been considerable interest in this year's seasonal flu vaccine. The following is an overview of all the adverse events following immunisation (AEFIs) reported to CARM associated with the seasonal flu vaccine in previous years (whether or not they have been considered by CARM to be causally related).
In the last decade, CARM has received between 91 and 135 reports per year where the seasonal flu vaccine has been suspected by the reporter to have caused an adverse event. These AEFIs can be grouped into various categories to give an overview of the reporting profile. The profile for seasonal flu vaccine is shown in Table 2 below. The table includes all 1509 reports received by CARM since the start of the adverse reactions reporting scheme in New Zealand in 1965 through to the end of September 2009.
Table 2: Profile of reported AEFI by category
Category# | Total number of events* |
---|---|
Alimentary | 246 |
Application site | 860 |
Cardiovascular | 244 |
Endocrine/Metabolic | 12 |
Haematological | 26 |
Liver | 5 |
Musculoskeletal | 210 |
Nervous System | 515 |
Other | 432 |
Procedure Related | 1 |
Psychiatric Changes | 188 |
Resistance Mechanism Disorders | 14 |
Respiratory | 186 |
Skin & appendages | 326 |
Special Senses | 83 |
Urinary | 3 |
Total | 3351 |
# CARM classification.
* The number of events is greater than the number of reports as one report may include one or more suspected reactions.
Over the last five years the reporting for most of the categories as a proportion of total reports for that year has been similar. The exceptions are a higher proportion of reports of dizziness in the cardiovascular category in 2006 and of injection site inflammation and pain in 2005 and 2007.
Table 3: The ten most commonly reported AEFIs for seasonal flu vaccine
Adverse event | Number | Category |
---|---|---|
Injection site inflammation | 456 | Application site |
Injection site pain | 214 | Application site |
Headache | 149 | Nervous system |
Dizziness | 122 | Cardiovascular |
Fever | 118 | Nervous system |
Myalgia | 97 | Musculoskeletal |
Nausea | 95 | Alimentary |
Urticaria | 77 | Skin and appendages |
Pruritus | 71 | Skin and appendages |
Injection site erythema | 66 | Application site |
There have been previous concerns that immunisation with influenza vaccine
may cause rare neurological or immunological effects such as Guillain-Barré
syndrome, facial/Bell's palsy or convulsions. Epidemiological studies have
not consistently found an association between these types of events and
seasonal flu vaccines.1,2 Since
1965 CARM has received 14 reports of Guillain-Barré syndrome, 7 reports
of facial palsy, 3 reports of Bells palsy, 5 reports of transverse myelitis
and 11 reports of convulsions. The reporting rate for all of these events
is lower than the background rate in the general population.3
A review of the reported AEFI by CARM and Medsafe has not altered the benefit risk balance for these vaccines which continues to be favourable.
Healthcare professionals are encouraged to continue to report suspected adverse reactions to all vaccines and medicines to CARM.
References
- Haber P, Sejvar j, Mikaeloff et al. 2009. Vaccine and Guillain-Barré Syndrome Drug Safety 32: 309-323.
- Stowe J, Andrews N, Wise L et al. 2006. Bell's palsy and parenteral inactivated influenza vaccine. Hum Vaccin 2: 110-2
- Black S, Eskola J, Siegrist CA et al. 2009. Importance of background rates of disease in assessment of vaccine safety during mass immunisation with pandemic H1N1 influenza vaccines. Lancet 374: 2115-22