Effect of Different Vaccines in H5N1 Pandemic Compared
Vaccine formulation with low antigen dose, non-aluminum adjuvant may be best option
THURSDAY, July 23 (HealthDay News) -- Vaccines against H5N1 influenza containing non-aluminum adjuvant might be the best formulation for immunizing the public in the event of a pandemic, according to research published in the August issue of The Lancet Infectious Diseases.
Lamberto Manzoli, M.D., of the University "G. d'Annunzio" of Chieti in Italy, and colleagues analyzed data from a meta-analysis that included 13 randomized controlled trials assessing 58 groups, which evaluated the effects of avian H5N1 vaccination.
The researchers found that vaccines with non-aluminum adjuvant elicited sufficiently high immunogenicity -- more than 70 percent -- even at low doses, such as 12 μg or less given as two doses. Higher doses didn't lead to substantial improvements. Aluminum-adjuvanted and non-adjuvanted vaccines showed lower immunogenicity, and even high doses didn't provide sufficient immunogenicity.
"Taken together, these findings suggest that, at present, the H5N1 vaccine formulation that includes a low antigen dose and a non-aluminum adjuvant (which, at such doses, is an oil-in-water emulsion-based adjuvant) might represent the best option in the case of a pandemic. Considering that lowest-dose vaccines would be strongly needed to allow rapid production and supply during a pandemic (an issue that is likely to be crucial because recourse to antiviral agents might be limited by suboptimum stocks and distribution logistics), a vaccine including 6 μg or lower and oil-in-water adjuvant could be a very useful option," the authors conclude.