Immunization schedule for Hib vaccine as recommended by IAP varies with
age. This schedule of lessening number of doses of vaccine with increase
in age is based on the premise that natural infection induces some
immunity and so less number of vaccine doses are needed with increase in
Why do we not recommend one dose of rotavirus vaccine
only (instead of 2 at present) if a child comes for vaccination at 4 to 6
months of age on the premise that the child may have developed partial
immunity by rotavirus infection by this time?
For varicella vaccine, why do we need two doses of
vaccine after 12 years of age?