Can a 9‑month‑old infant who has recovered from measles receive the oral polio vaccine now?

OPV Administration After Measles Recovery in a 9-Month-Old

Yes, you can and should administer OPV (or preferably IPV) to this 9-month-old infant now that they have recovered from measles, as there is no contraindication to polio vaccination following measles infection or recovery.

Timing of Polio Vaccination After Measles

• There is no required waiting period between measles illness recovery and polio vaccine administration 1
• The standard polio vaccination schedule should proceed based on the child's chronological age and previous vaccination history, not delayed by recent measles infection 2, 3
• At 9 months of age, this infant should have already received polio vaccine doses at 6 weeks, 10 weeks, and 14 weeks according to WHO-recommended schedules 1

Recommended Vaccine Type: IPV vs OPV

IPV is strongly preferred over OPV for the following reasons:

• IPV eliminates the risk of vaccine-associated paralytic poliomyelitis (VAPP) while providing equivalent protection (99-100% protective antibodies after three doses) 2, 3
• No serious adverse events have been linked to IPV use 2, 3
• Multiple countries have successfully eliminated polio using IPV-only schedules 2

However, if only OPV is available (common in pulse polio campaigns in endemic regions):

• OPV can be safely administered and is acceptable 1, 4
• The primary series consists of doses at 6 weeks, 10 weeks, and 14 weeks, with doses separated by minimum 6-week intervals 1

Determining Which Dose to Administer

Assess the infant's vaccination history:

• If the infant has received 0-2 prior polio vaccine doses: administer the next dose in the series immediately 5
• If the infant has received 3 doses: they have completed the primary series per WHO schedule 1
• The minimum interval between doses is 4 weeks for IPV and 6 weeks for OPV 1, 3, 5

Interchangeability of OPV and IPV

• If previous doses were OPV, IPV can and should be used to complete the series 2, 6
• Four doses of OPV or IPV in any combination constitutes a complete series 2, 6
• There is no need to restart the vaccine series regardless of time elapsed between doses 3, 5

Common Pitfalls to Avoid

• Do not delay vaccination waiting for an arbitrary period after measles recovery; there is no immunologic reason to wait 1
• Do not use reduced doses; full vaccine doses are required for adequate immune response 2
• Do not assume the child is fully vaccinated without written documentation of previous doses 1
• If administering OPV and the infant is hospitalized, consider IPV instead due to transmission risk 2