Estimating pneumococcal vaccine coverage among Australian Indigenous children and children with medically at-risk conditions using record linkage

Incremental effectiveness of 23-valent pneumococcal polysaccharide vaccine against pneumonia hospitalisation among Australian Indigenous children: A record linkage study

BACKGROUND

The impact of pneumococcal conjugate vaccines (PCVs) on pneumonia in children is well-documented but data on 23-valent pneumococcal polysaccharide vaccine (PPV23) are lacking. Between 2001 and 2011, Indigenous children in Western Australia (WA) were recommended to receive PPV23 at 18-24 months of age following 3 doses of 7-valent PCV. We evaluated the incremental effectiveness of PPV23 against pneumonia hospitalisation.

METHODS

Indigenous children born in WA between 2001 and 2012 who received PCV dose 3 by 12 months of age were followed from 18 to 60 months of age for the first episode of pneumonia hospitalisation (all-cause and 3 subgroups: presumptive pneumococcal, other specified causes, and unspecified). We used Cox regression modelling to estimate hazard ratios (HRs) for pneumonia hospitalisation among children who had, versus had not, received PPV23 between 18 and 30 months of age after adjustment for confounders.

RESULTS

11,120 children had 327 first episodes of all-cause pneumonia hospitalisation, with 15 (4.6%) coded as presumptive pneumococcal, 46 (14.1%) as other specified causes and 266 (81.3%) unspecified. No statistically significant reduction in all-cause pneumonia was seen with PPV23 (HR 1.11; 95% CI: 0.87-1.43), but the direction of the association differed for presumptive pneumococcal (HR 0.47; 95% CI: 0.16-1.35) and specified (HR 0.89; 95% CI: 0.49-1.62) from unspecified causes (HR 1.13; 95% CI: 0.86-1.49). During the baseline period before PPV23 vaccination (12-18 months), all-cause pneumonia risk was higher among PPV23-vaccinated than unvaccinated children (RR: 1.73; 95% CI: 1.30-2.28).

CONCLUSION

In this high-risk population, no statistically significant incremental effect of a PPV23 booster at 18-30 months was observed against hospitalised all-cause pneumonia or the more specific outcome of presumptive pneumococcal pneumonia. Confounding by indication may explain the slight trend towards an increased risk against all-cause pneumonia. Larger studies with better control of confounding are needed to further inform PPV23 vaccination.

Improving Pneumococcal Vaccination Rates in Cochlear Implant Programs: A Systematic Review and Meta-analysis

OBJECTIVE

To review the literature on pneumococcal vaccination compliance rates among cochlear implant (CI) patients and to examine the utility of intervention programs on increasing vaccination rates.

DATA SOURCES

PubMed, Scopus, and CINAHL.

REVIEW METHODS

A systematic review was performed following PRISMA guidelines. Studies of pneumococcal vaccination rates at baseline and before and after the implementation of a quality improvement (QI) intervention were included. A total of 641 studies were screened, and 13 studies met inclusion criteria. Meta-analyses of pneumococcal vaccination rates pre- and post-QI intervention in CI patients were performed.

RESULTS

A total of 12,973 children and adults were included. The baseline PCV13 and PPSV23 vaccination rates were 53.45% (95% CI, 37.02%-69.51%) and 42.53% (95% CI, 31.94%-53.48%), respectively. Comparing children and adults, PCV13 and PPSV23 baseline vaccination rates were not statistically significant. The PPSV23 vaccine rate after QI initiatives was significantly higher than the baseline rate at 83.52% (95% CI, 57.36%-98.46%). After these interventions, patients had a 15.71 (95% CI, 4.32-57.20, P < .001) increased odds of receiving PPSV23 vaccination compared to before QI implementation.

CONCLUSIONS

The baseline rates of PCV13 and PPSV23 are highly variable and lower than expected, given current vaccination recommendations for CI patients. QI programs appear successful in increasing compliance rates with the PPSV23 vaccination; however, they are still far from full compliance. Further intervention programs with stricter surveillance, monitoring, and follow-up systems are needed to achieve improved compliance with the PCV13 and PPSV23 vaccination in CI recipients.

A quality improvement study: Optimizing pneumococcal vaccination rates in children with cochlear implants

Children with cochlear implants are at increased risk of invasive pneumococcal disease, with national and international guidelines recommending additional pneumococcal vaccines for these children. This study aimed to examine the pneumococcal immunization status and rate of invasive pneumococcal disease in children with cochlear implants at a tertiary paediatric hospital over a 12-year period. Additionally, the impacts of vaccination reminders and a dedicated immunization clinic on pneumococcal vaccination rates were assessed. This quality improvement study included 200 children who had received a cochlear implant through the Children's Hearing Implant Program at a tertiary paediatric hospital servicing the state of Western Australia. The majority of children (88%) were not up to date with additionally recommended pneumococcal vaccinations. Over the 12-year study period, 2% of children developed invasive pneumococcal disease associated with cochlear implant infections. Generic and personalized electronic immunization reminders improved pneumococcal vaccine up-take in this paediatric cochlear implant setting from 12% (19/153) at baseline to 49% (75/153, p < 0.0001) post implementation. The value of a nurse-led dedicated immunization clinic was also demonstrated with all children (42/42, 100%) up to date with Prevenar13 and the majority (34/42, 81%) up to date with Pneumovax23 post initiation of this referral pathway. These data support the expansion of this model to other medically-at-risk paediatric groups that have been highlighted consistently to be under-vaccinated.

Infectious complications and optimising infection prevention for children with cochlear implants

AIM

To describe the clinical epidemiology of children receiving cochlear implants, as well as the management and outcomes of cochlear implant infections and adherence to infection prevention measures.

METHODS

A retrospective observational study was conducted in children ≤18 years who received cochlear implants in Western Australia's tertiary paediatric hospital. Information was obtained from medical and laboratory records regarding demographics, indication for implant, implant infection and preoperative Staphylococcus aureus screening/decolonisation. Immunisation history was examined using the Australian Immunisation Register.

RESULTS

Overall, 118 children received cochlear implants, with 158 devices inserted (599 cochlear implant insertion-years). An implant infection rate of 3.8% (6/158) was identified during the study period (four pneumococcal and two community-acquired methicillin resistant S. aureus infections). All required surgical management, with an overall median duration of antibiotic therapy of 37 days (interquartile range (IQR) 29-48) and median length of stay of 8 days (IQR 8-9.5). All devices were retained and there were no relapses or deaths. Half of the children who developed cochlear implant infections (50%, 3/6) were up-to-date with additional pneumococcal vaccinations and no children (0%, 0/118) received S. aureus screening/decolonisation before implant insertion.

CONCLUSIONS

Favourable outcomes were achieved with cochlear implant retention; however, the treatment was burdensome for families. We demonstrate significant scope to improve adherence to existing infection prevention strategies and provide direction for optimising preventative measures in the future. These include ensuring parental education, additional pneumococcal vaccinations and S. aureus decolonisation which are delivered as an infection prevention bundle to the growing population of infants receiving cochlear implants.

Effectiveness of 7-Valent Pneumococcal Conjugate Vaccine Against Invasive Pneumococcal Disease in Medically At-Risk Children in Australia: A Record Linkage Study

BACKGROUND

Children with chronic medical conditions are at higher risk of invasive pneumococcal disease (IPD), but little is known about the effectiveness of the primary course of pneumococcal conjugate vaccine (PCV) in these children.

METHODS

A cohort born in 2001-2004 from two Australian states and identified as medically at-risk (MAR) of IPD either using ICD-coded hospitalizations (with conditions of interest identified by 6 months of age) or linked perinatal data (for prematurity) were followed to age 5 years for notified IPD by serotype. We categorized fully vaccinated children as either receiving PCV dose 3 by <12 months of age or ≥1 PCV dose at ≥12 months of age. Cox proportional hazard modeling was used to estimate hazard ratios (HRs), adjusted for confounders, and vaccine effectiveness (VE) was estimated as (1-HR) × 100.

RESULTS

A total of 9220 children with MAR conditions had 53 episodes of IPD (43 vaccine-type); 4457 (48.3%) were unvaccinated and 4246 (46.1%) were fully vaccinated, with 1371 (32.3%) receiving dose 3 by 12 months and 2875 (67.7%) having ≥1 dose at ≥12 months. Estimated VE in fully vaccinated children was 85.9% (95% CI: 33.9-97.0) against vaccine-type IPD and 71.5% (95% CI: 26.6-88.9) against all-cause IPD.

CONCLUSION

This is the first population-based study evaluating the effectiveness of PCV in children with MAR conditions using record linkage. Our study provides evidence that the VE for vaccine-type and all-cause IPD in MAR children in Australia is high and not statistically different from previously reported estimates for the general population. This method can be replicated in other countries to evaluate VE in MAR children.