  We study the superconformal index of five-dimensional SCFTs and the sphere
partition function of four-dimensional gauge theories with eight supercharges
in the presence of co-dimension two half-BPS defects. We derive a prescription
which is valid for defects which can be given a "vortex construction", i.e. can
be defined by RG flow from vortex configurations in a larger theory. We test
the prescription against known results and expected dualities. We employ our
prescription to develop a general computational strategy for defects defined by
coupling the bulk degrees of freedom to a Gauged Linear Sigma Model living in
co-dimension two.
