Determinants of under-immunization and cumulative time spent under-immunized in a Quebec cohort. Issue 43 (13th October 2017)

• Record Type: Journal Article
• Authors: O'Donnell, Shauna; Dubé, Eve; Tapiero, Bruce; Gagneur, Arnaud; Doll, Margaret K.; Quach, Caroline
• Is Part Of: Vaccine. Volume 35:Issue 43(2017)
• Page Start: 5924
• Page End: 5931
• Publication Date: 2017-10-13
• Subjects: Vaccination coverage -- Age-appropriate immunization -- Under-immunization -- Determinants; AGE acute gastroenteritis -- CLSC Centre local de services communautaires -- CMA Census Metropolitan Area -- cNICS childhood National Immunization Coverage Survey -- FSA forward sortation area -- PIQ Quebec Immunization Protocol -- UTD up to date; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2017.08.072
• Languages: English
• ISSNs: 0264-410X

Abstract

Abstract: Background: Under-immunization refers to a state of sub-optimal protection against vaccine preventable diseases. Vaccine coverage for age may not capture intentional or non-intentional spacing of vaccines in the recommended provincial immunization guidelines. We aimed to identify factors associated with coverage and under-immunization and to determine the number of days during which children were under-immunized during their first 24 months of life. Methods: Secondary analysis of children ≤3 years recruited through active surveillance for gastroenteritis from three Quebec pediatric emergency departments from 2012 to 2014. Vaccination status for children at least 24 months of age was determined using provincial immunization guidelines. Cumulative days under-immunized were calculated for DTaP-VPI-Hib, PCV, MMR, and Men-C-C. Factors associated with up-to-date (UTD) status at 24 months of life and for under-immunization ≥6 months were analyzed using logistic regression. Results: Of 246 eligible children, 180 (73%) were UTD by 24 months of life. The mean cumulative days under-immunized for MMR was 107 days, for PCV 209 days, for Men-C-C 145 days, and for DTaP-VPI-Hib 227 days. Overall, 149 children (60%) experienced delay for at least 1 vaccine. Factors associated with both an UTD status at 24 months and concurrently associated with being under-immunization ≥6 months, included timely initiation of immunization (OR = 5.85; 95% CI: 2.80–12.22) and (OR = 0.13; 95% CI: 0.07–0.24), failure to co-administer 18-month vaccines (OR = 0.15; 95% CI: 0.10–0.21) and (OR = 3.29; 95% CI: 2.47–4.39), and having a household with ≥3 children under 18 years ((OR = 0.50; 0.28–0.86) and (OR = 2.99; 1.45–6.22), respectively. Conclusion: Paired with an unexpected low level of coverage at 24 months of life, the majority of our cohort also experienced a state of under-immunization for a least one vaccine. Estimates of coverage do not capture intentional or non-intentional gaps in protection from vaccine preventable illnesses. Timely preventive care should be prioritized.