Swine Flu Vaccine

Development and testing of an influenza vaccine can take about 6 months after identification of the particular strain involved. The time from initiation of vaccine production is expected to be approximately 19 weeks. Steps involved in the vaccine development process are:

* Step 1: Identification of virus (as soon as 24 hours)

* Step 2: Development of a Primary Seed (approximately 4 weeks)

* Step 3: Development and Production (approximately 12 additional weeks)

* Step 4: Testing (approximately 6 additional weeks)

* Step 5: Review and Authorization (approximately 1 additional week)

Two formulations of pH1N1 vaccine have been approved in Canada. Arepanrix™ H1N1 is an adjuvanted vaccine. The second formulation is an unadjuvanted vaccine, and is in production. The unadjuvanted vaccine is intended to be used for pregnant women. The rest of the population will receive the adjuvanted vaccine.

UNADJUVANTED VACCINE

The unadjuvanted vaccine is an inactivated, split virus product. The virus is propagated in eggs, and the vaccine is prepared using processes similar to the process for seasonal vaccines. The product contains 15 µg of influenza A/California/7/2009 (H1N1) antigen and 50 µg of thimerosal per 0.5 ml dose.

Arepanrix™

Arepanrix™ is the adjuvanted vaccine and has lower doses of antigen. Each 0.5 mL dose of Arepanrix™ contains 3.75 µg of haemagglutinin derived from influenza A/H1 N1/California/7/2009 antigen, 5 µg of thimerosal, and the adjuvant AS03. The adjuvant system AS03 contains squalene oil, a natural component of cell membranes (10.69 mg per dose), and DL-a-tocopherol (Vitamin E; 11.86 mg per dose). The adjuvant also contains 4.86 mg of polysorbate 80 (Tween 80), an emulsifier.

Adjuvanted vaccines are generally well tolerated and safe. The adjuvant used in the Canadian vaccine, AS03, has been tested in approximately 39,000 people around the world and has been evaluated by Health Canada.

WHAT THE STUDIES HAVE SHOWN.

The first clinical trial data with the GlaxoSmithKline (GSK) AS03-adjuvanted pH1N1 vaccine (in Europe) involved an initial study of 128 persons aged 18-60 years, in which 62 individuals received adjuvanted vaccine containing 5.25 µg of antigen per dose and 66 individuals received the unadjuvanted vaccine containing 21 µg of antigen per dose. Seroconversion rates at 21 days following the first vaccine dose were 98.4% and 95.5% for the adjuvanted and unadjuvanted vaccines respectively.

ADVERSE EVENTS WITH THE USE OF VACCINE

Symptom Adjuvanted vaccine (n=62) (%) Unadjuvanted vaccine (n=62) (%)
Pain 90.3 37.1
Redness 1.6 0.0
Swelling 6.5 0.0
Fatigue 32.3 25.8
Headache 14.3 7.6
Arthralgia (joint pain) 11.3 4.8
Myalgia (muscle ache) 33.9 8.1
Shivering 8.1 3.2
Sweating 9.7 8.1
Fever 0.0 0.0

Almost all symptoms were mild to moderate in severity. No serious adverse events have been reported.