Figure 7.

Measuring post-vaccine antibody responses using DBS sampling and the WHO International standard (NIBSC 20/136). DBS eluates obtained from 34 individuals who were ≥ 14 days post-immunisation are all reactive, demonstrating effectiveness at detecting vaccine-induced antibody responses. Binding Ratios (A) and inferred WHO International Units (B) from S1 IgG capture are displayed on a Log₂ scale, the line is the median, BR of 1 and WHO32 IU are the cut off values. (C) The relationship between S1 IgM and IgG capture Binding Ratios and WHO IU/ml, with BR displayed on Log₂ scale and IU/ml on a Log₁₀ scale. IgG IU/ml are shown with a circle and IgM IU/ml are shown with a triangle.