How many OPV doses are there?

4 doses

Generally, after four doses of OPV, a child should be protected against polio.  Anyway, specialists consider that it is safe to administer 4 or more doses of OPV to children.  The main idea is that the vaccine is designed to be administered multiple times to ensure full protection.   Needless to say, in the tropics where the weather is hot, keep in mind that more than 4 doses of OPV are required for a child to be fully protected.  There are cases when even more than ten doses are administered without side effects.