India, Oct. 27 -- When we think of the polio vaccine, it is usually the popular advertisements that come to mind - a veteran Bollywood actor reminding us to make sure that babies receive their 'two drops for life'. So when one encounters an injectable polio vaccine on the immunisation chart, it is reasonable for them to wonder why both are necessary.

In an interaction with HT Lifestyle on the occasion of World Polio Day, which was observed on October 24, paediatrician Dr Rohini Nagarkar explained how the two polio vaccinations differ, and why both are important in the effort to eradicate the disease.

There are three distinct types of poliovirus and two types of vaccines. The more popular one is the OPV, or oral polio vaccine. The second...