Zero dose of polio vaccine in which is give
the WHO programme on immunisation and the national immunisation programme in india recommend a primary course of 3 doses of OPV at one month intervals,commencing the first dose when infant is 6 weeks old.it is recommended that a dose of OPV (zero dose)is required to be given to all children delivered in health institutions before their discharge from hospital. ref:parks textbook ,22nd edition,pg no 187
Before giving DPT
At bih
When child is having diarrhoea
When child is having polio
Epidemiology