Create age mask

Converts a data frame of individual ages to give the index of the first infection that individual could have had

create_age_mask(DOBs, strain_isolation_times)

Arguments

DOBs	the vector of dates of birth, same time units as strain_isolation_times
strain_isolation_times	the vector of times that individuals can be infected

Value

a vector giving the first index of strain_isolation_times that an individual can be infected

Examples

data(example_titre_dat)
data(example_antigenic_map)
times <- example_antigenic_map$inf_times
DOBs <- unique(example_titre_dat[,c("individual","DOB")])
age_mask <- create_age_mask(DOBs$DOB, times)