A zero-dose vulnerability index for equity assessment and spatial prioritization in low- and middle-income countries - C.E. Utazi; H.M.T. Chan; I. Olowe; A. Wigley; N. Tejedor-Garavito; A. Cunningham; M. Bondarenko; J. Lorin; D. Boyda; D. Hogan; A.J. Tatem (Spatial Statistics, 2023)