Derivation
variable: dpt2date (table[s]: all_vaccination_records [derived table])
variable: birth_date (table[s]: all_vaccination_records [derived table])
*for DPT2, HH2, PCV2, RV2 and P2: problem if vacc date is less than 3 weeks, or more than 6 weeks after first dose (supposed to be 1 month after first dose)
if "`vacc'"=="dpt2" replace `vacc'Sprob=1 if (dpt2date-dpt1date<21 | dpt2date-dpt1date>42 | dpt1date==.) & dpt2date~=. & birth_date~=.