Tdap vaccine in pregnancy and immunogenicity of pertussis and pneumococcal vaccines in children: What is the impact of different immunization schedules?

BACKGROUND: In 2019, the 3 + 1 schedule for children's vaccination (2-4-6-18 months old) was changed for a reduced 2 + 1 schedule (2-4-12 months old) in Quebec, Canada. We compared the post-booster anti-pertussis and anti-pneumococcus IgG antibody concentrations among children of Tdap-vaccinated and unvaccinated mothers for different vaccine schedules and vaccine formulations. METHODS: We conducted an observational cohort study. An invitation letter to potential participants was provided during a routine vaccination visit. Children's blood samples were analyzed post-booster at 13 (2 + 1 schedule) or 19 (3 + 1 schedule) months of age for antibodies against pertussis antigens (pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (PRN)) and pneumococcal antigens (serotypes 4, 18C, 19A, and 19F). IgG concentrations among children of Tdap-vaccinated and unvaccinated mothers for each vaccination schedule were compared using geometric mean concentrations (GMCs) and GMC ratios (GMRs), adjusting for potentially immune-response-influencing factors (aGMR). Serotype-specific pneumococcal seroprotection rates were also compared. RESULTS: A total of 360 children were included for pertussis analysis and 248 for pneumococcal analysis. For the 2 + 1 schedule, 13-month-old children of Tdap-vaccinated mothers had lower GMCs against PT, FHA, and PRN, with aGMR (95 %CI) of 0.77 (0.65-0.90), 0.66 (0.55-0.79), 0.72 (0.52-0.99), respectively. For the 3 + 1 schedule, at 19 months old, the interference appeared to be attenuated (higher aGMR values). GMCs against PT were slightly higher in the 3 + 1 than the 2 + 1 schedule: 126.5 IU/ml vs 91.6 IU/ml; aGMR = 1.27. GMCs against PT, FHA and PRN were slightly higher among children who received Infanrix hexa® compared to those who received Pediacel® at 12 months old. For pneumococcal antibodies, at 13 months old, there was no strong evidence of immune interference in children of Tdap-vaccinated mothers. CONCLUSION: Infant vaccination schedule may influence immune interference associated with maternal Tdap vaccination. More studies are needed to assess the clinical impact of this interference on children's protection.

International comparison of injury care structures, processes, and outcomes between integrated trauma systems in Québec, Canada, and Victoria, Australia.

BACKGROUND: Quality improvement activities in trauma systems are widely based on comparisons between trauma centers within the same system. Comparisons across different trauma systems may reveal further opportunities for quality improvement. OBJECTIVES: This study aimed to compare the integrated trauma systems in Québec, Canada and in Victoria, Australia, regarding their structures, care processes and patient outcomes. METHODOLOGY: The elements recommended by the American College of Surgeons were used to compare trauma systems structures. Comparisons of care processes and patient outcomes were based on data from major trauma admissions extracted from trauma registries (2013 and 2017). Care processes included time to reach a definitive care facility, time spent in the emergency department, and time lapsed before the first head computed tomography (CT) scan. These care processes were compared using a z-test of log-transformed times. Hospital mortality and hospital length of stay (LOS) were compared using indirect standardization based on multiple logistic and linear regression. RESULTS: Major differences in trauma system structure were Advanced Trauma Life Support at the scene of injury (Victoria), the use of validated prehospital triage tools (Québec), and mandatory accreditation of all trauma centers (Québec). Patients in Québec arrived at their definitive care hospital earlier than their counterparts in Victoria (median: 1.93 vs. 2.13 h, p = 0.002), but spent longer in the emergency department (median: 8.23 vs. 5.15 h, p<0.0001) and waited longer before having their first head CT (median: 1.90 vs. 1.52 h, p<0.0001). In-hospital mortality and hospital LOS were higher in Québec than in Victoria (standardized mortality ratio: 1.15, 95% CI: 1.09 - 1.20; standardized LOS ratio: 1.10, 95% CI: 1.09 - 1.11). CONCLUSION: We observed important differences in the structural components and care processes in Québec and Victoria's trauma systems, which might explain some of the observed differences in patient outcomes. This study shows the potential value of international comparisons in trauma care and identifies possible opportunities for quality improvement.

COVID-19 pandemic impact on childhood vaccination coverage in Quebec, Canada.

Response measures to mitigate the coronavirus disease 2019 pandemic impacted access to routine vaccination services. We evaluate the impact of the pandemic on routine infant vaccination uptake by comparing vaccination coverage, vaccine delays and doses administered in 2019 and 2020, in Quebec, Canada. Using a population-based vaccination registry, we compared vaccination coverage at 3, 5, 13 and 19 months of age between 2019 and 2020 cohorts each month from January to November. For vaccine delays, we measured the cumulative proportion vaccinated in each targeted cohort monthly. We also compared the measles-containing vaccines administered before 24 months of age between the same period in 2019 and 2020. A decline in vaccination coverage and children vaccinated on time was observed in all cohorts during the first months of the pandemic. The greatest impact was observed for the 18-month vaccination visit with a difference in vaccination coverage between both cohorts of 30.9% in May. Measles-containing doses administered during the first months of the pandemic were lower in 2020 compared with 2019: -21.1% in March (95%CI-21.6;-20.4), and -39.2% in April (95%CI-40.0;-38.2). After May, the coverage increased for all cohorts to reach pre-pandemic levels after a few months for most target ages. Routine childhood vaccinations were affected during the first months of the pandemic, but catch-up occurred thereafter and vaccination coverage in affected cohorts were very close to levels of 2019 after a few months of follow-up. Real-time monitoring of childhood vaccination is essential but also for other vaccination programs, severely affected by the pandemic.