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July 2006 Literature Review Safety and immunogenicity of an inactivated split-virion influenza A/Vietnam/1194/2004 (H5N1) vaccine: phase I randomized trial This is a report from the UK and France of an attempt to develop a vaccine for avian influenza. The test strain was an attenuated strain of influenza A/Vietnam/1194/2004/NIBRG14 (H5N1). The study was done on 300 volunteers in six groups of 50 using three doses (7.5 ug, 15 ug and 30 ug) with each dose given with or without alum adjuvant. Each patient received a single vaccination followed by a second vaccination at 21 days. Serum samples were obtained at 0 (baseline), 21 and 42 days to determine hemagglutination-inhibition activity. Results showed optimal response with two doses of adjuvantated 30 ug formulation; 67% developed a HI seroconversion after two vaccinations. The other doses did not show an improved response with adjuvant. These results are summarized in the following table:
*vaccine + aluminum hydroxide adjuvant Conclusion: The authors conclude that the double dose regimen with 30 ug inactivated H5N1 adjuvanted vaccine was safe and showed an immune response that was “consistent with European regulatory requirements for licensure." Comment: These results are similar to those reported previously by Treanor and coworkers [N Engl J Med 2006;354:1343]. One difference is the use of alum adjuvant in the study reported above, but this did not consistently promote any more pronounced immune response. Many would conclude that both studies are depressing in terms of the need for a large volume of vaccine as well as the requirement for a boosting dose. With regard to volume, the current influenza vaccine uses a single dose of 15 ug for adults; the results reported here and by Treanor would require a massive increase in production capacity to meet the goal of avian influenza vaccine for the entire country. Literature Review by John G. Barlett, MD, Professor, Division of Infectious Diseases | |||||||||||||||||
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