Preparing for an Influenza Pandemic: A Phase I Study of a Parenterally Administered H5N1 Influenza Vaccine in Healthy Adults

Detailed Summary

The safety and tolerability of the pandemic A/H5N1 virosomal vaccine formulated with or without the 3rd generation ISCOM™ adjuvant for parenteral administration will be investigated locally and systemically and by using haematological, biochemical and immunological screening tests. The immunogenicity of the H5N1 vaccine will be assessed through the induction of local and systemic antibody and cellular immune responses. In a pandemic situation, an important aspect is the rapidity of the immune response to the H5N1 vaccine so the detailed kinetics of the immune response will be investigated. The capacity of the vaccine to elicit long lasting immunity and cross reactive immunity to H5 viruses will also be evaluated. Furthermore, the quality of the immune response induced by the vaccine will be studied. The vaccine will be administered as twice the normal human dose (30μg HA) with and without adjuvant, and in a dose sparing manor of half (7.5μg HA) and one tenth (1.5μg HA) of the normal human dose with adjuvant. Sixty subjects will receive two doses of virosomal H5N1 influenza vaccine (separated by 21 ± 4 days) by intramuscular injection into the deltoid muscle. Escalating doses will be separated by a period of one week. Four groups each containing 15 subjects will receive two doses of the pandemic virosomal A/H5N1 influenza vaccine containing: Group 1 30µg HA IM, Group 2 1.5µg HA adjuvanted with 50µg 3rd generation ISCOM™ IM, Group 3 7.5µg HA adjuvanted with 50µg 3rd generation ISCOM™ IM, Group 4 30µg HA adjuvanted with 50µg 3rd generation ISCOM™ IM.

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