Patterns of reporting
In the first six months of the program, from 30 September 2009 to 31 March 2010, approximately eight million doses of Panvax and 330 000 doses of Panvax Junior were distributed in Australia. During this period, the TGA received 1614 reports of adverse events associated with H1N1 vaccination.
The highest number of reports was received in October 2009, when there were 696 adverse event reports. By January 2010 numbers had fallen to around 80 reports per month. A second, smaller peak in reporting occurred in March, with 145 reports (Fig. 2). The TGA suspects the second peak was caused by a second wave of promotion of the program by the Department of Health and Ageing, the start of school-based programs in some states and territories, and catch-up reporting following the vacation period.
Types of reactions reported
Most of the 1614 reports received were mild and common problems such as headache, gastrointestinal upset, and injection-site soreness, swelling or redness (Table 1). Most of the adverse effects reported were well recognised and listed in the Product Information for Panvax and Panvax Junior.
Table 1 Commonly reported reactions to H1N1 vaccination during the first six months of the Australian vaccination program
Reaction
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Number of cases
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% reports containing one or more of these terms
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Pain (excluding injection-site pain)
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388
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24%
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Malaise, lethargy, fatigue, asthenia
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360
|
22%
|
Influenza-like illness, cough, rhinorrhoea, oropharyngeal pain
|
346
|
21%
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Vomiting, diarrhoea
|
317
|
20%
|
Headache
|
303
|
19%
|
Pyrexia
|
280
|
17%
|
Rash (any type), pruritus, urticaria
|
269
|
17%
|
Injection-site reaction or injection-site pain
|
240
|
15%
|
Nausea
|
203
|
12.5%
|
Neurological events
Several neurological adverse events of special interest were closely monitored. One of the concerns raised was a possible association between Guillain-Barré syndrome and vaccination. This concern arose from the observation that in the United States the 1976 influenza vaccine was associated with an excess risk of Guillain-Barré syndrome of nine in every one million vaccinees in the six weeks following vaccination.2 This association has not been seen since. The TGA convened an expert panel to assist in developing case definitions and clinical follow-up templates and to review cases. In total, 10 reports of Guillain-Barré syndrome were received by the TGA in the first six months of the program. This is within the background rate that would be expected for an unvaccinated population.
Allergy and anaphylaxis
The occurrence of allergy and anaphylaxis was also closely monitored by the TGA. Anaphylaxis and allergic reactions are not predictable and can occur in anyone regardless of whether they have a history of allergy or not. There were nine cases of anaphylaxis reported and all recovered without sequelae.
There was one case of anaphylaxis reported in a person with a latex allergy who had previously received seasonal trivalent vaccines without any allergic response. The TGA investigated whether latex may have been coming into contact with the vaccine, including commissioning studies in Europe. Investigations showed that latex was not detectable in the vaccine, even when the syringe was damaged or abnormal or the rubber bung of the syringe was crushed.
Convulsions
The number of reports of convulsion associated with H1N1 vaccination is of particular interest. The 2010 seasonal trivalent influenza vaccination program was suspended for children five years and under, following a higher than usual number of reports of febrile convulsion associated with vaccination. In the first six months of the H1N1 vaccination program there were seven reports of febrile convulsion, all of which were in children under five years. Two of these cases occurred in association with varicella vaccine. The Product Information documents for Panvax and Panvax Junior include the occurrence of convulsions as an uncommon event, occurring in 1 in 1000 to 1 in 10 000 cases. More than 300 000 doses of Panvax Junior have been distributed, and so these figures provide reassurance that the non-adjuvant H1N1 vaccine does not produce an excess risk of convulsions in children.
New structural arrangements
The TGA officially launched a new organisational structure on 1 July 2010. This new structure will support the TGA's delivery of appropriate, consistent, effective and efficient regulation into the future.
Post marketing safety functions for all types of therapeutic products are managed by the Office of Product Review, which is part of the Monitoring and Compliance Group.
The implementation of the new structure is being carefully managed to ensure that current regulatory activities are maintained. The main contact points for reporting suspected reactions to medicines are unchanged, and information for health professionals and consumers – such as alerts, advisories and Medicines Safety Update – will continue to be published as usual.
Detailed information on the new structural arrangements is available at www.tga.gov.au/about/structure-new.htm
What to report? You don't need to be certain, just suspicious!
The TGA encourages the reporting of all suspected adverse reactions to medicines, including vaccines, over-the-counter medicines, herbal, traditional or alternative remedies. We particularly request reports of:
- all suspected reactions to new medicines
- all suspected medicines interactions
- suspected reactions causing death, admission to hospital or prolongation of hospitalisation, increased investigations or treatment, or birth defects.
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Reports may be submitted:
For more information about reporting, visit www.tga.gov.au or contact the TGA's Office of Product Review on 1800 044 114.
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DISCLAIMER
Medicines Safety Update is aimed at health professionals. It is intended to provide practical information to health professionals on medicine safety, including emerging safety issues. The information in Medicines Safety Update is necessarily general and is not intended to be a substitute for a health professional's judgment in each case, taking into account the individual circumstances of their patients. Reasonable care has been taken to ensure that the information is accurate and complete at the time of publication. The Australian Government gives no warranty that the information in this document is accurate or complete, and shall not be liable for any loss whatsoever due to negligence or otherwise arising from the use of or reliance on this document.
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