ED50 and PD50 comparison between seasonal and pandemic H1N1, and pandemic H5N1 vaccines.

n.a. not applicable (no challenge model available).1 based on an HI titer of ≥40.2 based on a MN titer of ≥20.3 based on the titer of infectious virus in the lungs of mice 3 days after challenge.4 based on survival of mice 14 days after challenge.Groups of mice were immunized twice with serial dilutions of antigen doses up to 5 µg of seasonal H1N1 (H1N1 A/Brisbane/59/2007), pandemic H1N1 (H1N1 A/California/7/2009) and pandemic H5N1 (H5N1 A/Vietnam/1203/2004) vaccines. The minimum antigen dose that resulted in seroconversion (ED50) or protection against challenge (PD50) of 50% of immunized animals was determined, and is given as mean with standard deviation (SD) and number of study replicates tested (N).