September 2025 Board of Health Meeting - Student Immunization Coverage Report in Windsor-Essex County Information Report

In Ontario, the Immunization of School Pupils Act (ISPA) R.S.O. 1990 requires children and adolescents attending elementary or secondary school to be immunized against measles, mumps, rubella, varicella, diphtheria, tetanus, pertussis, polio, and meningococcal disease, or have a valid Medical, or Conscience      (Religious Belief) exemption on file at the Health Unit. As outlined in the Ontario Public Health Standards (OPHS), health units in Ontario are required to have a complete immunization record, or a valid exemption on file, for every student attending school in their area. The WECHU assessed the immunization records for all students in Windsor and Essex County (WEC) for the 2024-2025 school year. Updates on ISPA implementation program interventions, for both elementary and secondary schools, were shared as a part of the May 2025 WECHU Board of Health Meeting package. The purpose of this report is to share updated immunization coverage rates among 7, 12, and 17-year-olds and highlight program interventions and areas of opportunity.

Immunization Compliance and Coverage Rates

Immunization compliance rate refers to the proportion of a population that is appropriately immunized or have approved exemptions (medical and non-medical) for a vaccine preventable disease (VPD) based on legislation (e.g., under the ISPA) at a point in time.

Immunization coverage rate describes the proportion of a population that is appropriately immunized, based on the Publicly Funded Immunization Schedules for Ontario, for a VPD at a point in time. Achieving and maintaining high immunization coverage amongst school age children is essential for effective prevention and control of infectious diseases. Immunization coverage rates for ISPA required vaccines and strongly recommended school age vaccines are presented in Table 1 below.

1. Vaccination with Meningococcal C conjugate vaccine.
2. Vaccination with Meningococcal A, C, Y, W-135 conjugate vaccine.
3. Hepatitis B and HPV are recommended and offered to 12-year-olds during their grade 7 year.

DISCUSSION

For the 2024–25 school year, immunization coverage rates for ISPA-required vaccines among 7- and 17-year-olds in WEC are all above the provincial averages. Many coverage rates are close to, and some exceed (highlighted in green in the above table), the national goals. Compared to the previous school year, coverage has been maintained or improved. For example, among 17-year-olds, Diphtheria coverage increased from 80.86% to 90.45%, Pertussis from 80.66% to 90.54%, and Tetanus from 80.98% to 90.47% — all now meeting the 90% national goal. Local available temporal trends of immunization coverage rates among 7- and 17-year-olds is presented on the WECHU’s Immunization Coverage for School Pupils Data Dashboard.

Notably, Varicella continues to show lower coverage in 17-year-olds (53.92% in 2024–25), despite a modest increase from 47.69% in the previous year. This can be attributed to the fact that these students were born in 2007, before the ISPA required Varicella vaccination, amended in September 2014. Now the ISPA requires children born on or after 2010 to be vaccinated against Varicella-zoster – a herpes virus that causes chickenpox.

Under the Publicly Funded Immunization Schedules for Ontario, Grade 7 students are eligible for free vaccination against Hepatitis B, HPV, and Meningococcal disease. Hepatitis B and HPV vaccination are not required under the ISPA but are strongly recommended. The WECHU administers these vaccines through in school and in-house clinics, as well as dispenses them to community health care providers (HCP) upon request. 

Coverage rates for Hepatitis B and HPV among 12-year-olds in WEC remain higher than provincial averages. For instance, HPV coverage among 12-year-olds increased from 59.41% to 62.92% and Hepatitis B from 68.94% to 71.59% for the 2024–25 school year. Coverage among 17-year-olds declined in 2024–25 compared to the previous year (Hepatitis B: from 78.26% to 75.40%; HPV: from 70.47% to 65.45%). Both are now below the provincial average (2023–24) and well below the national goal of 90%, indicating room for continued improvement. 

The apparent decline in Hepatitis B and HPV immunization coverage among 17-year-olds may be partly attributed to improved reporting from private schools. In previous years, some private schools did not consistently submit immunization records, resulting in underrepresentation of a population less likely to receive these non-mandatory vaccines. With more private schools now submitting records, a greater number of under-immunized students are reflected in the data, contributing to a lower overall coverage rate. This shift represents improved data completeness rather than a true decline in vaccine uptake.

Additionally, ongoing pandemic-related challenges continue to impact vaccine catch-up efforts, particularly for non-ISPA vaccines like Hepatitis B and HPV. Many students are still catching up on missed doses due to interruptions in school-based vaccination programs. Furthermore, a significant number of these vaccines are administered by community HCPs and may not be consistently reported to the WECHU. As a result, administered doses may go unrecorded in the provincial database, further contributing to an underestimation of true coverage rates for these vaccines. 

In WEC, students with a properly filed medical or non-medical (philosophical) exemption remain compliant with the ISPA and are permitted to attend school, unless temporarily excluded during an outbreak or disease exposure for public health reasons. Philosophical exemptions account for most immunization exemptions locally, representing 5.3% of all enrolled students (3,559 out of 67,096 students). This pattern is consistent across 7-, 12-, and 17-year-olds, with private schools demonstrating notably high proportions of philosophical exemptions, often exceeding 90% of total exemptions. However, it is important to note that some students with exemptions on file may still be partially or fully immunized. This can occur for various reasons, such as receiving vaccines after filing an exemption or selective acceptance of certain vaccines. The WECHU will continue to explore a more detailed breakdown of immunization status among students with immunization exemptions. 

CONCLUSION

Immunization  remains one of our population’s best defenses against vaccine preventable diseases. Supporting provincially funded vaccine programs remains a priority for the WECHU. Although the WECHU has higher coverage rates compared to the provincial average for all ISPA-required vaccines, there are opportunities to improve coverage rates in WEC, especially for non-mandated vaccine such as Hepatitis B and HPV. 

The WECHU continues to focus on strategies to reduce barriers to vaccination in alignment with the 2025-2030 Interim National Immunization Strategy (NIS) – particularly vaccine confidence and uptake, which is a key pillar of focus. Continued engagement with private schools and efforts to support vaccine access and reporting among these populations will be important to ensure equitable immunization coverage across all school settings. 

Another key strategy, in particular to support continual improvement of coverage rates amongst 7- year olds, is to improve the process for the collection and assessment of immunization information for children attending licensed childcare centres in our community. This upstream approach aims to engage with families earlier to improve coverage rates in WEC by ensuring vaccinations are administered on schedule throughout childhood. 

Additional proactive interventions underway include the following:

• Reaching students and their families in June of the school year preceding their Grade 7 year to provide in-class education sessions on the routine school-based vaccine program as well as opening the online consent form to allow more time for completion and follow up.
  • The WECHU immunization nurses reached out to individual families throughout the summer to obtain consent, offer support, and answer questions. This resulted in obtaining close to 3,000 consents prior to the start of the school year.
• In collaboration with community partners, the WECHU immunization nurses participated in community events focused on newcomers and priority populations to provide education, review/update immunization records, book appointments, and obtain Grade 7 vaccine consent.
• New immunization education video resources were developed for both parent/guardian and student audiences, with closed captions available in multiple languages. 

To ensure ongoing protection from vaccine preventable diseases, the WECHU remains committed to continued collaborations with school boards, school administration, community health care providers, and community agencies.