Changes in Post‐Transplant Vaccine Coverage After Implementing Structured Vaccine Reviews in Pediatric Solid Organ Transplant Recipients in British Columbia, Canada: A Canadian Immunization Research Network Study
Florence Anne Barbey, Manish Sadarangani, Catherine Burton, Simon Urschel, Shannon E. MacDonald, Athena McConnell, Estelle Morin, Kevin Meesters, Tom Blydt‐Hansen, Elaine Yong, Hana Mitchell,ABSTRACT
Background
Children with solid organ transplants (SOT) are at increased risk of infections but may be under‐vaccinated. In 2021, our center implemented structured post‐SOT vaccine reviews. We conducted a single‐center, pre‐post observational study with a repeated cross‐sectional design to assess changes in vaccine coverage from 2020 to 2024.
Methods
We performed a chart review of SOT recipients aged 2–18 years who were ≥ 1 year post‐transplant and followed at our clinic on March 1, 2020, and/or March 1, 2024. Patients eligible at both time points (repeat participants) were included in both cohorts; those eligible once (single‐time‐point participants) were included in the respective cohort. We assessed individual and overall vaccine coverage, defined as receipt of all recommended non‐live, non‐seasonal vaccines. Comparisons used the chi‐square and paired McNemar's test (two‐sided p < 0.05).
Results
Overall vaccine coverage increased from 33% in 2020 to 51% in 2024. The most prominent changes were observed for 23‐valent pneumococcal polysaccharide (PPV23) and human papillomavirus (HPV) vaccines, with significant improvements among both single‐time‐point (PPV23: 58%–88%, p < 0.001; HPV: 32%–81%, p = 0.003) and repeat participants (PPV23: 52%–76%, p = 0.008; HPV: 20%–53%, p = 0.008). Overall vaccine coverage among patients transplanted at age < 2 years was significantly lower compared to older children in 2020 but not in 2024.
Conclusions
Structured post‐transplant vaccine reviews were associated with an increase in coverage across most vaccines and all organ subgroups, supporting its integration into routine post‐transplant care and prospective, multicenter evaluation.