Lists, by table, the column each scorecard input is read from. Keys shared
with calc_polio_indicators() take the same defaults. Override any of them
through the cols argument, for example
cols = list(campaigns = list(vaccine_type = "vaccine_type")).
Details
The samples keys sabin and target each take several columns. A sample
has Sabin (or target) virus detected when any of those columns is TRUE, a
non-zero number or a non-blank string. By default target virus is WPV1 or
VDPV2.
The isolation defaults are the column names that
calc_es_site_performance() returns, so its result can be passed as
isolation directly.
