Applies a modifier to severity and transmission parameters
modify_severity(efficacy, efficacy_strain_2, strain_severity_modifier)Vaccine efficacy parameters for strains 1 and 2 respectively. Expects a list with names rel_susceptibility, rel_p_sympt, rel_p_hosp_if_sympt, rel_infectivity, rel_p_death. Element columns correspond to vaccine strata and rows to age groups.
List of modifiers to be applied to efficacy
variables; length should correspond to number of strains and each element
should be a list with same names as efficacy
Returns a list with same length and names as efficacy and where
each element has dimensions n_groups x n_strains x n_vacc_strata