1. Given too early (before the minimum interval of 4 weeks from the 1st dose):
The 2nd dose is invalid.
Repeat the dose ensuring at least 4 weeks after the previous valid dose.
2.Correct age and route, but given at 2 and half months instead of 14 weeks:
If both doses (e.g., at 6 and 10 weeks) were valid (4-week gap, IM route), you may still give a 3rd IPV dose at 9 months or later to complete the schedule .
Health Tips
if 4 weeks have passed completely, nothing to worry.