Figure 1.

Densities of cumulative sample sizes accrued across dose investigation studies planned by programmes developing in an age group and stratifying recruitment. Listed are numbers of programmes developing in each age group. The sample size range is [0−40] in the top panel and [0−150] in the bottom. Overall median samples per age group are: 0.1 aged 0–27 days; 2.9 aged 1–23 months; 10.0 aged 2–11 years; 9.0 aged 12–17 years. , overall; , orphan; , non-orphan(A) 0–27 days; 15 programmes. (B) 1–23 months; 23 programmes, (C) 2–11 years; 41 programmes and (D) 12–17 years; 47 programmes