654 suspected adverse reactions to Panvax reported to Australia's TGA in one month

The Australian national immunization program with the H1N1 2009 influenza vaccine Panvax, made by French drug major Sanofi-Aventis' Sanofi-Pasteur unit, began on September 30, 2009, and the country's Therapeutic Goods Administration has been closely monitoring any side effects from the use of the vaccine.

As at October 29, a total of 654 suspected side effects have been reported to the TGA following vaccination with Panvax in Australia, with over 3.75 million doses of the vaccine distributed in the country. The great majority of reported side effects have been mild and common problems such as headache, gastrointestinal upset, soreness, swelling, or redness at the injection site. Most of the side effects that have been reported are well recognized and listed in the Panvax Product Information, and the TGA's assessment and the advice of its expert committees is that Panvax is a safe, effective vaccine for prevention of the H1N1 influenza.

Common side-effects reported following Panvax administration are shown below:

Suspected adverse reaction Number of reports (% of total reports for Panvax*

Nausea, vomiting or diarrhoea 178 (27%)
Headache 149 (23%)
Fatigue, lethargy, general weakness 101 (15%)
Fever 97 (15%)
Cough, runny nose or sore throat 88 (14%)
Injection site reaction 87 (13%)
Muscle or joint pain 75 (12%)
Flu-like symptoms 71 (11%)
* The total exceeds 100% because each report can contain more than one reaction, for example, an injection site reaction and flu-like symptoms.

However, the TGA noted that an important category of possible reactions to any vaccine is allergy. Severe allergic reactions, such as anaphylaxis, may require adrenaline injections or other. As at October 29, the TGA had received six reports of possible anaphylaxis following vaccination with Panvax. The TGA, together with its expert advisory committee, the Adverse Drug Reactions Advisory Committee (ADRAC), has thoroughly investigated the details of these suspected cases of anaphylaxis. Using the Brighton Collaboration criteria for defining anaphylaxis1 the TGA, following advice from ADRAC, has concluded that only four of the reported cases were likely to have been associated with the vaccine. All cases reported to the TGA to date have either been treated appropriately or have resolved without treatment.

Again, while the exact patient-exposure for Panvax is unknown, based on distribution figures for Panvax, it appears the current observed rate of anaphylaxis is within the range expected for anaphylaxis post-immunization.