In touch but not up-to-date: Ambulatory visits and vaccination status in a cohort of young Swiss children

Vaccine Hesitancy in Central Switzerland: Identifying and Characterizing Undervaccinated Children in a Pediatric Emergency Department

Vaccinations play an important role in the prevention of potentially fatal diseases. Vaccine hesitancy has become an important problem both in the public discourse and for public health. We aimed to identify and characterize this potentially unvaccinated or incompletely vaccinated group of children presenting to the pediatric emergency department (PED) of the tertiary children's hospital in central Switzerland, a region that has anecdotally been claimed as a hotspot for vaccine hesitancy. All patients presenting to the PED (N = 20,247) between September 2018 and September 2019 were screened for their vaccination status and categorized as incomplete, unvaccinated, or fully vaccinated in a retrospective cohort study. Some 2.6% (n = 526) visits to the PED were not or incompletely vaccinated according to age, or their vaccination status was unknown. Most of the children in the cohort were not critically ill, and the minority had to be hospitalized. Undervaccinated patients were overrepresented in rural areas. Of all cohort visits, 18 (3.4%) patients received opportunistic vaccination in the PED. No cases of vaccine-preventable diseases were observed. In summary, incompletely vaccinated and unvaccinated status was less frequent than initially expected. The PED may play a role in increasing vaccination coverage by providing opportunistic vaccinations.

Childhood vaccination coverage and regional differences in Swiss birth cohorts 2012-2021: Are we on track?

AIMS

Many western countries are challenged by delayed and insufficient vaccination coverage rates in children, and thus missing WHO coverage targets. This study aimed to estimate vaccination coverage and timeliness in Swiss children over a decade. Furthermore, we evaluated the impact of COVID-19, regional variations, and the adherence to the amended vaccination schedule in 2019.

METHODS

Retrospective observational study with Swiss health insurance claims data including birth cohorts 2012-2021 of children continuously observed until ages 13, 25, and 48 months respectively. We used population-weighted proportions and time-to-event analyses to describe coverage and timeliness of diphtheria/tetanus/pertussis/poliomyelitis/haemophilus influenzae type b (DTaP-IPV-Hib), measles/mumps/rubella (MMR), hepatitis B (HBV), pneumococcal (PCV), and meningococcal (MCV) vaccinations according to the national schedule. The potential impact of COVID-19 and vaccination schedule adherence were evaluated descriptively. Logistic regression was used to investigate regional factors potentially associated with non-vaccination.

RESULTS

120,073 children, representing between 12 and 17 % of all Swiss children born in corresponding years, were included. Coverage remained stable or improved over the years. The 2019 amendment of the national immunization schedule was associated with an increase of ~10 % points in full coverage in Swiss children for DTaP-IPV-Hib, MMR and HBV despite the concurrent COVID-19 pandemic. Nonetheless, full vaccination coverage remained below 90 % with many vaccination series being delayed or not completed. The comparison across the different vaccines revealed large differences in coverage. Moreover, we observed large regional differences in non-vaccination with children living in rural and German-speaking areas more likely to be entirely unvaccinated.

CONCLUSION

Full vaccination coverage in Swiss children is still below 90 % with many vaccinations administered delayed. Given regional differences, missed or delayed booster vaccinations, and differences in vaccine-specific acceptability, more effort may be needed to achieve national vaccination targets.

Protective immune responses against Haemophilus influenza type b elicited by a fully-liquid DTaP-IPV-Hib-HepB vaccine (VAXELIS™)

BACKGROUND

DTaP-IPV-Hib-HepB is a fully-liquid, hexavalent combination vaccine (Vaxelis™) approved for vaccination against diphtheria, tetanus, pertussis, poliomyelitis, hepatitis B, and invasive disease due to Haemophilus influenzae type b (Hib). Hib capsular polysaccharide, polyribosylribitol phosphate (PRP), is conjugated to Neisseria meningitidis outer membrane protein complex (OMPC). Safety and immunogenicity of DTaP-IPV-Hib-HepB were evaluated in 6 Phase III clinical studies including > 5,200 children. Studies included vaccination schedules in the United States (2, 4, 6 months of age) and Europe (2, 3, 4, 12 months of age and 2,4,11-12 months of age).

METHODS

Data pertaining to anti-PRP responses of DTaP-IPV-Hib-Hep B compared to control vaccines from 5 Phase III studies are summarized.

RESULTS

Post-infant series, the percentage of participants that achieved protective antibody thresholds for PRP (anti-PRP titer ≥ 0.15 μg/mL and ≥ 1.0 μg/mL, respectively) were higher in DTaP-IPV-Hib-HepB recipients compared to recipients who received control vaccines. A high level of protective responses (96.6% at ≥ 0.15 μg/mL [95% CI:94.8, 97.9%]; 72.9% at ≥ 1.0 μg/mL [95% CI:69.2,76.4%]) were seen post-dose 2 of the 2 + 1 vaccination schedule and met superiority criteria over comparator, p-value < 0.001. In the same schedule, prior to administration of the toddler dose (in the second year of life), anti-PRP titers were higher in DTaP-IPV-Hib-HepB recipients (91.4% at ≥ 0.15 μg/mL; 46.8% at ≥ 1.0 μg/mL) as compared to recipients who received control vaccines (63.4% at ≥ 0.15 μg/mL; 17.1% at ≥ 1.0 μg/mL). One-month post-toddler dose, high levels of anti-PRP titers were achieved in both DTaP-IPV-Hib-HepB recipients (99.8% at ≥ 0.15 μg/mL; 96.6% at ≥ 1.0 μg/mL) and recipients who received control vaccines (99.5% at ≥ 0.15 μg/mL; 94.9% at ≥ 1.0 μg/mL).

CONCLUSIONS

These results support that DTaP-IPV-Hib-HepB induces a robust and sustained early Hib response. During the high-risk period for Hib disease after the infant vaccine and prior to the toddler dose; >90% of recipients maintained superior protective anti-PRP levels compared to control.

Coverage rates and timeliness of nationally recommended vaccinations in Swiss preschool children: A descriptive analysis using claims data

BACKGROUND

Low vaccination coverage as well as incomplete and delayed vaccinations pose a risk for the individual and population protection from vaccine-preventable diseases.

AIM

To describe vaccination patterns for nationally recommended basic and supplementary vaccinations in Swiss preschool children.

METHODS

We performed a descriptive study based on administrative claims data from a large Swiss health insurer (Helsana), in cohorts of children born between January 2010 and December 2016. We assessed coverage rates of nationally recommended basic vaccinations (i.e., diphtheria, tetanus, acellular pertussis [DTaP], Haemophilus influenzae type b [Hib], poliomyelitis [IPV], measles, mumps, and rubella [MMR]) and supplementary vaccinations (i.e., pneumococcal conjugate vaccine [PCV] and meningococcal group C conjugate vaccine [MCV]) for each birth cohort at the age of 13, 25, and 37 months. Additionally, we analysed timeliness of vaccinations using inverse Kaplan-Meier curves. Results were extrapolated to the Swiss population.

RESULTS

The study population comprised 563,216 children. We observed continuously increasing coverage rates for all vaccinations until the 2015 birth cohort. Overall, up-to-date status for the first dose of studied vaccinations at 37 months was as follows: DTaP: 95.4%; Hib: 94.9%; IPV: 95.5%; MMR: 86.8%; PCV: 83.2%; and MCV: 66.7%. On average, however, only seven out of ten children had an up-to-date status for completed basic vaccinations; even less (six out of ten) were up-to-date for recommended supplementary vaccinations at 37 months of age. Moreover, 4% of all analysed children received none of the recommended vaccinations and there were substantial regional differences. Delays in vaccine administration were common. The most frequently postponed basic vaccination was MMR; 22.6% of children vaccinated with the first dose experienced delays relative to age-appropriate standards.

CONCLUSION

To avoid future outbreaks and transmission of vaccine-preventable diseases, vaccination coverage in Switzerland must be further improved. In addition, more emphasis should be placed on timely vaccination.

Age appropriateness of vaccination with recommended childhood vaccines in Sri Lanka

Vaccination status is conventionally measured by up-to-date coverage. This method does not take in to account whether the vaccines were received at the correct age and interval which is essential for optimal disease protection. Sri Lanka – a lower middle-income country in the Indian Ocean, has previously presented with high vaccination coverage for all childhood vaccines. However, few studies investigating timeliness of vaccinations have until now been carried out in Sri Lanka.

Aim: This study was carried out to investigate the individual coverage and age appropriateness of vaccination, in two different demographic settings in Anuradhapura district, Sri Lanka. The study of cross-sectional descriptive design included 633 children born in 2011. Public Health Midwives kept hand-written documentation of the birth and vaccination dates on each child in her geographic area. Vaccination ages were then compared to the timelines of vaccination provided by the Epidemiology Unit of Sri Lanka.

The vaccination coverage for all antigens was 97.5% (94.2–99.7%) at age 5–6 years. Timeliness of doses was between 65.0 and 88.6 % (median 80.7%; 65.0–88.6) and significantly lower in the urban population compared to the rural. The present study shows that the vaccine coverage in both urban and rural areas in Sri Lanka was high and that the timeliness predominantly followed national recommendations.