MEDICAL ADVISORY: Implications for Children Previously Immunized with Oral Polio Vaccine

Issued by: Dr. Jessica Jackman, MD MPH FRCPC FACPM DipABLM, Associate Medical Officer of Health

Date: January 24, 2025

The purpose of this alert is to revisit the updated recommendations for children previously immunized with oral polio vaccine (OPV) on or after April 1, 2016 and emphasize implications for students during the current immunization record review.

Ontario’s updated recommendations for children previously immunized with OPV

The Ontario Ministry of Health released a memorandum to health care providers, which Niagara Region Public Health amplified in a July 2024 Medical Advisory. In summary:

Individuals vaccinated on or after April 1, 2016 with OPV are presumed to have received bivalent OPV. Bivalent OPV contains poliovirus serotypes 1 and 3, but not serotype 2. These doses are invalid and do not count towards completion of a polio vaccine series.
An unknown polio product received outside of Canada on or after April 1, 2016 is invalid as it may be OPV. DPTP means that the product types are unknown, including polio.
If OPV and a monovalent inactivated polio vaccine (IPV) were administered on the same day, on or after April 1, 2016, they are both considered invalid doses, as the IPV would have been a fractional dose
If OPV and a combination product that contains IPV (e.g. Tdap-IPV) were administered on the same day, on or after April 1, 2016, the IPV dose is considered valid

Implications

This change impacts ongoing vaccination assessments under the Immunization of School Pupils Act (ISPA) and the Child Care and Early Years Act (CCEYA). Some children who have been previously considered up to date for polio now require additional polio vaccine (IPV) doses.
- In Niagara, a total of 1,400 students have received one or more invalid polio dose(s) and now require IPV to be up-to-date for polio
- Additionally, another 2,000 students in Niagara without an immunization record on file could potentially report an OPV vaccine
As per the 2025 Immunization Record Review Timelines, Public Health will be sending suspension orders at the end of February to any student who remains non-compliant with the ISPA

Health Care Provider Action

For protection against all three poliovirus types, ensure that patients who received OPV on or after April 1, 2016 have received a sufficient number of trivalent polio vaccine doses (as per their age appropriate schedule)
When you see students that have received an Immunization Reminder Notice from Public Health for polio, please follow Ontario’s updated recommendations for children previously immunized with OPV on or after April 1, 2016
- If a student is flagged as overdue for polio by Public Health, it is based on the vaccinations that we have on file for that student in ICON. Please note in order to determine the type of polio vaccine product received in ICON, you will need to go to the far-right column “Additional Info.” If an immunization record does not state IPV or OPV, then the polio type is unknown and assumed to be OPV.
- If the student’s record in ICON is up-to-date with what your office has on file, please provide them with vaccinations as indicated by Public Health in their Immunization Reminder Notice
- If the student’s record in ICON is not up-to-date with what your office has on file (including the type of polio vaccine received):
  - Provide any missing vaccine(s) if required; if you are unsure of the vaccination(s) required for the student to be up-to-date, call Public Health at the number below
  - Give the parent/legal guardian an updated record and advise them to report the vaccine(s) to Public Health
Use the General Vaccine Order Form to place an order for vaccine

More information

Call the Vaccine Preventable Disease program at 905-688-8248 or 1-888-505-6074 ext. 7396
Public Health Ontario’s Summary of Immunization Recommendations for Children Previously Immunized with Oral Poliovirus Vaccine
If you need a patient’s immunization record in order to provide service, follow the instructions in the October Physicians’ Newsletter for Accessing and Updating Immunization Records