Why should injectable polio vaccine be given?

Q: When should my 6 months old son be vaccinated against Hepatitis B. Also, why has my son's paediatrician asked to administer polio vaccine (three injections with one month apart) to my kid even though he is taking polio drops?

A:Hepatitis B (Hib) vaccine should have been given with DPT vaccine but you can also give it now. Injectable polio vaccine in addition to oral polio vaccine will give slightly more protection but is costly.