A study of Samoan, Tongan, Cook Island Maori, and Niuean infant care practices in the Growing Up in New Zealand study.

BACKGROUND: Despite a low rate of infant mortality, Aotearoa New Zealand has a high rate of Sudden Unexpected Death in Infants (SUDI), with disproportionate impact for Pacific infants. This study explored the infant care practices, factors and relationships associated with increased risk of SUDI amongst Tongan, Samoan, Cook Islands Maori, and Niuean mothers in New Zealand, to inform evidence-based interventions for reducing the incidence of SUDI for Pacific families and their children. METHODS: Analysis comprised of data collected in 2009-2010 from 1089 Samoan, Tongan, Cook Islands Maori and Niuean mothers enrolled in the Growing Up in New Zealand longitudinal cohort study. The sleeping environment (bed-sharing and sleep position) of the infants was assessed at 6 weeks. Multivariable logistic regression analysis were conducted, controlling for sociodemographic factors to explore the association between selected maternal and pregnancy support and environment factors and the sleeping environment for infants. RESULTS: Mothers who converse in languages other than English at home, and mothers who consulted alternative practitioners were less likely to follow guidelines for infant sleeping position. Similarly language, smoking, alcohol, household dwelling, crowding and access to a family doctor or GP were associated with mothers following guidelines for bed-sharing. CONCLUSION: The impact of SUDI on Pacific infants may be lessened or prevented if communication about risk factors is more inclusive of diverse ethnic, cultural worldviews, and languages. Societal structural issues such as access to affordable housing is also important. This research suggests a need for more targeted or tailored interventions which promote safe sleeping and reduce rates of SUDI in a culturally respectful and meaningful way for Pasifika communities in Aotearoa, New Zealand.

Forecasting severe respiratory disease hospitalizations using machine learning algorithms.

BACKGROUND: Forecasting models predicting trends in hospitalization rates have the potential to inform hospital management during seasonal epidemics of respiratory diseases and the associated surges caused by acute hospital admissions. Hospital bed requirements for elective surgery could be better planned if it were possible to foresee upcoming peaks in severe respiratory illness admissions. Forecasting models can also guide the use of intervention strategies to decrease the spread of respiratory pathogens and thus prevent local health system overload. In this study, we explore the capability of forecasting models to predict the number of hospital admissions in Auckland, New Zealand, within a three-week time horizon. Furthermore, we evaluate probabilistic forecasts and the impact on model performance when integrating laboratory data describing the circulation of respiratory viruses. METHODS: The dataset used for this exploration results from active hospital surveillance, in which the World Health Organization Severe Acute Respiratory Infection (SARI) case definition was consistently used. This research nurse-led surveillance has been implemented in two public hospitals in Auckland and provides a systematic laboratory testing of SARI patients for nine respiratory viruses, including influenza, respiratory syncytial virus, and rhinovirus. The forecasting strategies used comprise automatic machine learning, one of the most recent generative pre-trained transformers, and established artificial neural network algorithms capable of univariate and multivariate forecasting. RESULTS: We found that machine learning models compute more accurate forecasts in comparison to naïve seasonal models. Furthermore, we analyzed the impact of reducing the temporal resolution of forecasts, which decreased the model error of point forecasts and made probabilistic forecasting more reliable. An additional analysis that used the laboratory data revealed strong season-to-season variations in the incidence of respiratory viruses and how this correlates with total hospitalization cases. These variations could explain why it was not possible to improve forecasts by integrating this data. CONCLUSIONS: Active SARI surveillance and consistent data collection over time enable these data to be used to predict hospital bed utilization. These findings show the potential of machine learning as support for informing systems for proactive hospital management.

Charting elimination in the pandemic: a SARS-CoV-2 serosurvey of blood donors in New Zealand.

New Zealand has a strategy of eliminating SARS-CoV-2 that has resulted in a low incidence of reported coronavirus-19 disease (COVID-19). The aim of this study was to describe the spread of SARS-CoV-2 in New Zealand via a nationwide serosurvey of blood donors. Samples (n = 9806) were collected over a month-long period (3 December 2020-6 January 2021) from donors aged 16-88 years. The sample population was geographically spread, covering 16 of 20 district health board regions. A series of Spike-based immunoassays were utilised, and the serological testing algorithm was optimised for specificity given New Zealand is a low prevalence setting. Eighteen samples were seropositive for SARS-CoV-2 antibodies, six of which were retrospectively matched to previously confirmed COVID-19 cases. A further four were from donors that travelled to settings with a high risk of SARS-CoV-2 exposure, suggesting likely infection outside New Zealand. The remaining eight seropositive samples were from seven different district health regions for a true seroprevalence estimate, adjusted for test sensitivity and specificity, of 0.103% (95% confidence interval, 0.09-0.12%). The very low seroprevalence is consistent with limited undetected community transmission and provides robust, serological evidence to support New Zealand's successful elimination strategy for COVID-19.

'O'ofaki: a health promotion and community development concept to bring Pasifika people together.

Stable, healthy families are the loto or heart of strong Pacific communities. This paper addresses the problem of a decline in the strength of Pacific families. It introduces and discusses the Tongan concept of O'ofaki, as the way in which shared, core relational commitments can bring Pasifika peoples together to support one another for health and community development. This process is based on a reciprocal sharing of social capital to promote cultural solidarity and social justice. We describe two studies by the lead author, through which the concept of O'ofaki emerged. The first study utilized an action research model while the second study focused on two Pasifika-centric research approaches: talanga, which is a Tongan word for interactive talking for a purpose, and the kakala (Tongan garland) research approach. The latter approach is incorporated within a general inductive methodology as well as luva-the dissemination of the results. Finally, the paper focuses on the components of O'ofaki and its application to Pasifika communities.

Pneumococcal Conjugate Vaccines Turning the Tide on Inequity: A Retrospective Cohort Study of New Zealand Children Born 2006-2015.

BACKGROUND: Hospitalization rates for infectious diseases in New Zealand (NZ) children have increased since 1989. The highest burden is among Maori and Pacific children, and the most socioeconomically deprived. New Zealand introduced pneumococcal conjugate vaccine (PCV)7 in June 2008, PCV10 in 2011, and PCV13 in 2014. METHODS: A retrospective cohort study of NZ children aged <6 years between 2006 and 2015 was performed using administrative databases. Demographics and hospitalizations were linked to evaluate the impact of the PCV vaccination program on cases of invasive pneumococcal disease (IPD), all-cause pneumonia (ACP), and otitis media (OM), defined by ICD-10-AM codes, and to explore the effect by ethnicity and deprivation. RESULTS: Between 2006 and 2015, there were 640 children hospitalized with IPD, 26589 for ACP, and 44545 for OM. IPD hospitalizations declined by 73% between 2005 and 2015 for children <6 years of age, whereas ACP and OM declined by 8% and 25%, respectively. The highest rates for all diseases were among Maori and Pacific children and those from high deprivation. However, the declines were highest among Maori and Pacific children and those from socioeconomically deprived areas. IPD hospitalizations declined by 79% and 67% for Maori and Pacific children, respectively, between 2006 and 2015. ACP declined by 12% in Maori and 21% in Pacific children. OM declined by 51% in Maori children. CONCLUSION: In contrast to the increasing trend of hospitalization rates for infectious disease in New Zealand, the use of PCV appears associated with reductions in ethnic and socioeconomic disparities in hospitalization for IPD, ACP, and OM.

Comparison of vaccination coverage of four childhood vaccines in New Zealand and New York State.

AIM: To ensure that children are vaccinated, different national governments use diverse strategies. We compared childhood vaccination coverage rates between New York State (NYS) and New Zealand (NZ) as the vaccination strategies are different. METHODS: We used vaccination records from the NYS Immunisation Information System and the National Immunisation Register of NZ to measure (i) vaccination coverage by school entry and by age six; (ii) coverage of different socio-demographic groups; and (iii) trend in vaccination coverage between 2011 and 2015. RESULTS: We analysed the records of 583 767 NYS children and 269 800 NZ children 7 years of age. NZ children were 3.3-21.5% more likely than NYS children to receive each of the vaccines. Compared to NYS, NZ children were 39.6% more likely to be up-to-date by the start of school and 28.1% more likely to be up-to-date by age 6 years. Both NYS and NZ had statistically significant increases in the proportion of children who were up to date on each vaccine and all vaccines by the start of school and by 6 years of age (P < 0.001). CONCLUSIONS: We identified under-vaccinated groups and examined the point in the vaccine series where children were most vulnerable to being under-vaccinated. This information is useful in targeting future investigations and interventions aimed at mitigating disparities in vaccine coverage. This comparison of regions with different vaccination programmes and policies is important when considering whether the particular vaccination coverage strategies of one region could be adapted and applied for the benefit of another.

Effectiveness of a group B outer membrane vesicle meningococcal vaccine against gonorrhoea in New Zealand: a retrospective case-control study.

BACKGROUND: Gonorrhoea is a major global public health problem that is exacerbated by drug resistance. Effective vaccine development has been unsuccessful, but surveillance data suggest that outer membrane vesicle meningococcal group B vaccines affect the incidence of gonorrhoea. We assessed vaccine effectiveness of the outer membrane vesicle meningococcal B vaccine (MeNZB) against gonorrhoea in young adults aged 15-30 years in New Zealand. METHODS: We did a retrospective case-control study of patients at sexual health clinics aged 15-30 years who were born between Jan 1, 1984, and Dec 31, 1998, eligible to receive MeNZB, and diagnosed with gonorrhoea or chlamydia, or both. Demographic data, sexual health clinic data, and National Immunisation Register data were linked via patients' unique personal identifier. For primary analysis, cases were confirmed by laboratory isolation or detection of Neisseria gonorrhoeae only from a clinical specimen, and controls were individuals with a positive chlamydia test only. We estimated odds ratios (ORs) comparing disease outcomes in vaccinated versus unvaccinated participants via multivariable logistic regression. Vaccine effectiveness was calculated as 100×(1-OR). FINDINGS: 11 of 24 clinics nationally provided records. There were 14 730 cases and controls for analyses: 1241 incidences of gonorrhoea, 12 487 incidences of chlamydia, and 1002 incidences of co-infection. Vaccinated individuals were significantly less likely to be cases than controls (511 [41%] vs 6424 [51%]; adjusted OR 0·69 [95% CI 0·61-0·79]; p<0·0001). Estimate vaccine effectiveness of MeNZB against gonorrhoea after adjustment for ethnicity, deprivation, geographical area, and sex was 31% (95% CI 21-39). INTERPRETATION: Exposure to MeNZB was associated with reduced rates of gonorrhoea diagnosis, the first time a vaccine has shown any protection against gonorrhoea. These results provide a proof of principle that can inform prospective vaccine development not only for gonorrhoea but also for meningococcal vaccines. FUNDING: GSK Vaccines.

An intervention to reduce the number of convenience stores selling tobacco: feasibility study.

BACKGROUND: Reduction of the availability of tobacco has been proposed as a means of reducing and denormalising tobacco use. Some retailers have stopped selling tobacco. Therefore, we investigated how willing New Zealand convenience store owners were to stop selling tobacco or sell nicotine replacement therapy. Promotion of their stores was offered as an incentive to stop selling tobacco. METHODS: We asked convenience store owners in the Auckland metropolitan region of New Zealand to choose one of three actions. The first was to stop selling tobacco for a short period of time; the second was to restrict the hours that they sold tobacco; the third was to display and sell nicotine replacement therapy. All participating retailers completed a short interview about selling tobacco. We also surveyed customers about nicotine replacement and cessation. RESULTS: One-third of eligible retailers agreed to participate. Most who participated (93%) were unwilling to stop or restrict tobacco sales and 2 (7%) had already stopped selling tobacco. Tobacco was perceived as a key product for their businesses. Very few customers who purchased cigarettes noticed nicotine replacement therapy or obtained it from convenience stores. CONCLUSIONS: Substantially reducing the availability of tobacco in communities is likely to require legislative approaches, underpinned by sustained community pressure and support for convenience store owners who are willing to change their business model.

Pertussis epidemiology in adults: Retrospective analysis of pertussis incidence and association with comorbidities among adult populations in Aotearoa New Zealand, using national administrative datasets.

BACKGROUND: In New Zealand, approximately half reported pertussis cases are adult. Studies indicate underestimated pertussis burden in this population and probable reservoir for childhood pertussis. Pertussis is linked to chronic obstructive pulmonary disease (COPD) development and increased risk with pre-existing COPD. While acellular pertussis vaccines are available for adults, data on pertussis disease burden in adults and association with COPD remain limited. AIM: To estimate pertussis incidence in New Zealand adult health service user (HSU) population aged ≥ 18 between 2008-2019 and inform adult pertussis vaccination strategies by assessing disease burden and risk factors in different adult populations. METHODS: Retrospective observational cohort study using an HSU cohort, formed by linking administrative health data using unique National Health Index identifier. For primary analysis, annual incidence rates were calculated using pertussis hospitalisations and notifications. In secondary analysis, Cox proportional hazards survival analyses explored association between pertussis in adults and chronic comorbidities. RESULTS: The cohort had 2,907,258 participants in 2008 and grew to 3,513,327 by 2019, with 11,139 pertussis cases reported. Highest annual incidence rate of 84.77 per 100,000 PYRS in 2012, notably affecting females, those aged 30-49 years, and European or Maori ethnicity. Adjusting for sociodemographic variables found no significant risk of prior pertussis notification leading to comorbidity diagnosis (Adjusted-HR: 0.972). However, individuals with prior comorbidity diagnosis had 16 % greater risk of receiving pertussis notification or diagnosis (Adjusted-HR: 1.162). CONCLUSIONS: Study found significant pertussis burden among the HSU adult cohort and highlighted higher risk of pertussis for those with recent comorbidity diagnoses. Vaccination for pertussis should be recommended for individuals with comorbidities to reduce infection risk and disease severity. GPs must have capability to test for pertussis, given it is notifiable disease with implications for individuals, their families, and broader population. High-quality disease surveillance is crucial for informing policy decisions.

Comparison of the Burden and Temporal Pattern of Hospitalisations Associated With Respiratory Syncytial Virus (RSV) Before and After COVID-19 in New Zealand.

BACKGROUND: Changes in the epidemiology of illnesses caused by respiratory syncytial virus (RSV) infection following the COVID-19 pandemic are reported. The New Zealand (NZ) COVID-19 situation was unique; RSV community transmission was eliminated with the 2020 border closure, with a rapid and large increase in hospitalizations following the relaxation of social isolation measures and the opening of an exclusive border with Australia. METHODS: This active population-based surveillance compared the age-specific incidence and seasonality of RSV-associated hospitalizations in Auckland, NZ, for 2 years before and after the 2020 border closures. Hospitalisation rates between years were compared by age, ethnicity (European/other, Maori, Pacific and Asian) and socioeconomic group (1 = least, 5 = most deprived). RESULTS: There was no RSV transmission in 2020. In all other years, hospitalisation rates were highest for people of Pacific versus other ethnic groups and for people living in the most deprived quintile of households. RSV hospitalisation rates were higher in 2021 and 2022 than in 2018-19. The epidemic peak was higher in 2021, but not 2022, and the duration was shorter than in 2018-19. In 2021, the increase in RSV hospitalisation rates was significant across all age, sex, ethnic and socioeconomic groups. In 2022, the increase in hospitalisation rates was only significant in one age (1- < 3 years), one ethnic (Asian) and one socioeconomic group (quintile 2). CONCLUSIONS: COVID pandemic responses altered RSV-related hospitalisation seasonal patterns. Atypical features of RSV hospitalisation epidemiology were the increase in rates in older children and young adults, which lessened in 2022. Despite these variations, RSV hospitalisations in NZ continue to disproportionately affect individuals of Pacific ethnicity and those living in more socioeconomically deprived households. Whilst future public health strategies focused on RSV disease mitigation need to consider the potential shifts in epidemiological patterns when the transmission is disrupted, these variances must be considered in the context of longer-standing patterns of unequal disease distribution.

Severe Acute Respiratory Infection (SARI) due to Influenza in Post-COVID Resurgence: Disproportionate Impact on Older Maori and Pacific Peoples.

OBJECTIVE: Influenza reemerged after a 2020-2021 hiatus in 2022, but understanding the resurgence needs pre-COVID era surveillance. We compared age- and ethnicity-specific incidence of severe acute respiratory infection (SARI) from a hospital network in Auckland, New Zealand, in 2022 against a baseline, 2012-2019. METHODS: Annual and monthly influenza SARI incidence per 1000 persons by age and ethnic group between 2012 and 2022 was calculated using resident population as the denominator. The hospitals capture most severe illness of the resident population. RESULTS: Influenza SARI incidence was highest among <1 year olds (2.62; 95% CI: 1.84-3.61) during 2012-2019, lowest at 6-14 years, and did not significantly increase until 50-64 years (0.35; 95% CI: 0.27-0.45), reaching 1.19 (95% CI: 0.57-1.55) in those ≥75 years. In all age groups, incidence was at least threefold higher in Maori and Pacific Peoples. No influenza SARI was identified in 2020-2021. In 2022, despite an early peak, annual incidence (<65 years) was lower than baseline in all ethnic groups, but incidence (≥65 years) in Maori (2.06; 95% CI: 1.22-3.26) and Pacific (3.94; 95% CI: 2.97-5.13) peoples was higher in 2022 than most baseline years, whereas incidence in NMNP (0.22; 95% CI: 0.14-0.32) was lower than any baseline year. CONCLUSION: After no influenza 2020-2021, Auckland had an early, high, narrow peak in 2022. Stratification by age and ethnicity revealed striking discrepancies in incidence among Maori and Pacific adults over 65 years compared with NMNP adults, with implications for targeted vaccination strategies.

Paediatric COVID-19 vaccination coverage and associated factors among migrant and non-migrant children aged 5-11 years in Aotearoa New Zealand: A population-level retrospective cohort study.

OBJECTIVE: Children with migrant and refugee backgrounds may experience immunisation inequities due to barriers to accessing and accepting vaccines. In Aotearoa New Zealand (NZ), national reporting can mask inequities in coverage by migration background. This study explored paediatric COVID-19 vaccine uptake among children with migrant and refugee backgrounds. METHODS: This population-level retrospective cohort study compared rates and determinants of paediatric COVID-19 vaccine uptake as of July 2022 amongst migrant and non-migrant children who were aged between 5 and 11 years as of January 2022. Linked de-identified administrative and health data available in Statistics NZ's Integrated Data Infrastructure were used, and univariate and multivariable logistic regression were conducted to determine associations. RESULTS: Of the total study population (N = 451,323), 3.5% were overseas-born migrant children, 31.3% were NZ-born migrant children, and 65.3% were NZ-born non-migrant children. Only 50.8% (229,164 out of 451,323) of children had received at least one dose. Migrant children were significantly more likely to have received a COVID-19 vaccination than non-migrant children. Logistic modelling revealed that all factors, including ethnicity, gender, age, family type, household income, deprivation, region, parent COVID-19 vaccination status, and child's previous COVID-19 infection, significantly influenced COVID-19 vaccine uptake. The largest contributing factor was parents' COVID-19 vaccination status. CONCLUSIONS: The findings suggest that NZ's paediatric COVID-19 vaccination programme was able to address logistical and motivational barriers commonly identified amongst migrants and refugees. IMPLICATIONS FOR PUBLIC HEALTH: As parents' vaccination status is an important factor in vaccinating their own children, continuous efforts are needed to support confident parental COVID-19 vaccine decision-making. To address social inequities, engagement with marginalised communities to co-design tailored and localised approaches is recommended.

MMR vaccine coverage and associated factors among overseas-born refugee children resettled in Aotearoa New Zealand: a national retrospective cohort study.

Background: Refugee children may be under-immunised against common vaccine-preventable diseases due to a myriad of factors related to their migration journey. Methods: This retrospective cohort study explored the rates and determinants of enrolment on the National Immunisation Register (NIR) and measles, mumps and rubella (MMR) coverage among refugee children up to 18 years old who resettled in Aotearoa New Zealand (NZ) from 2006 to 2013. Univariate and multivariable logistic regression were conducted to determine associations. Findings: Of the cohort (N = 2796), two thirds of the children (69%) were enrolled on the NIR. Among this sub-cohort (n = 1926), less than one third (30%) were age-appropriately vaccinated with MMR. MMR coverage was highest among younger children and improved over time. Logistic modelling revealed that visa category, year of arrival, and age group were significant factors that influenced NIR enrolment and MMR vaccine uptake. Those arriving via asylum seeking, family reunification and humanitarian pathways were less likely to be enrolled and vaccinated compared to refugees who entered under the national quota programme. More recent arrivals and younger children were more likely to be enrolled and vaccinated compared to children who arrived in NZ longer ago and were older. Interpretation: Resettled refugee children have suboptimal NIR enrolment and MMR coverage rates which varied significantly by visa category, highlighting the need for immunisation services to better engage with all refugee families. These findings suggest that broad structural factors related to policy and immunisation service delivery may influence the differentials seen. Funding: Health Research Council of New Zealand (18/586).

Childhood vaccination uptake among children born in Aotearoa New Zealand based on parental nationality.

Migrants and refugees generally experience immunization inequities compared to their host populations. Childhood vaccination coverage rates are influenced by a complex set of interrelated factors, including child and parental nativity. Coverage rates for MMR, pertussis, and HPV vaccines were compared among children born in Aotearoa New Zealand (NZ) of overseas-born parents or NZ-born parents. A nationwide retrospective cohort study was conducted using linked, de-identified data. Logistic regression models examined the most influential factors contributing to differences in timely vaccine uptake. Of the total study population who had received all scheduled vaccines (N = 760,269), 32.9% were children of migrant parents. Children of migrant parents had higher rates of complete and timely uptake for MMR, pertussis, and HPV vaccinations compared to non-migrant children. NZ-born children of migrant parents were significantly more likely to receive MMR and pertussis-containing vaccines on-time compared to those of non-migrants. All included factors, except for the child's gender and parents' English ability, significantly influenced vaccine uptake. Among NZ-born children of migrant parents, additional logistic modeling found significant differences based on parental duration of residence, visa group, and region of nationality. Findings point to the importance of differentiating between parent versus child nativity when examining immunization coverage. While vaccination rates were higher for NZ-born children of migrant parents, compared to non-migrant parents, timely coverage rates across both groups were below national targets. Continued efforts are needed to improve timely immunization service delivery to address suboptimal and inequitable coverage.

Likelihood-based estimation and prediction for a measles outbreak in Samoa.

Prediction of the progression of an infectious disease outbreak is important for planning and coordinating a response. Differential equations are often used to model an epidemic outbreak's behaviour but are challenging to parameterise. Furthermore, these models can suffer from misspecification, which biases predictions and parameter estimates. Stochastic models can help with misspecification but are even more expensive to simulate and perform inference with. Here, we develop an explicitly likelihood-based variation of the generalised profiling method as a tool for prediction and inference under model misspecification. Our approach allows us to carry out identifiability analysis and uncertainty quantification using profile likelihood-based methods without the need for marginalisation. We provide justification for this approach by introducing a new interpretation of the model approximation component as a stochastic constraint. This preserves the rationale for using profiling rather than integration to remove nuisance parameters while also providing a link back to stochastic models. We applied an initial version of this method during an outbreak of measles in Samoa in 2019-2020 and found that it achieved relatively fast, accurate predictions. Here we present the most recent version of our method and its application to this measles outbreak, along with additional validation.

A retrospective cohort study investigating the comparative effectiveness of pneumococcal vaccines against hospitalisation with otitis media and pneumonia in New Zealand.

BACKGROUND: Since 2008 New Zealand has used three different formulations of pneumococcal vaccines on the national infant schedule, PCV7, PCV10 and PCV13, switching between PCV10 and PCV13 twice in 10 years. We have used New Zealand's linkable, administrative health data to examine the comparative risk of otitis media (OM) and pneumonia hospitalisations among children receiving three different pneumococcal conjugate vaccines (PCV). METHODS: This was a retrospective cohort study using linked administrative data. Outcomes were otitis media, all cause pneumonia and bacterial pneumonia related hospitalisation for children in three cohorts representing periods where PCVs transitioned between PCV7, PCV10, PCV13 and back to PCV10 between 2011 and 2017. Cox's proportional hazard regression was used to provide hazard ratio estimates to compare outcomes for children vaccinated with different vaccine formulations and to adjust for different sub population characteristics. RESULTS: Each observation period, where different vaccine formulations coincided, and therefore comparable with respect to age and the environment, included over fifty-thousand infants and children. PCV10 was associated with a reduced risk for OM compared with PCV7 (Adjusted HR 0.89, 95 %CI 0.82-0.97). There were no significant differences between PCV10 and PCV13 in risk of hospitalisation with either otitis media or all-cause pneumonia amongst the transition 2 cohort. In the 18 -month follow-up, after transition 3, PCV13 was associated with a marginally higher risk of all-cause pneumonia and otitis media compared to PCV10. CONCLUSION: These results should offer reassurance about the equivalence of these pneumococcal vaccines against the broader pneumococcal disease outcomes OM and pneumonia.

Who are Pacific peoples in terms of ethnicity and country of birth? A cross sectional study of 2,238,039 adults in Aotearoa New Zealand's Integrated Data Infrastructure.

Background: The aggregation of Indigenous peoples from Pacific Island nations as 'Pacific peoples' in literature may mask diversity in the health needs of these different groups. The aim of this study was to examine the heterogeneity of Pacific groups according to ethnicity and country of birth. Methods: Anonymised individual-level linkage of administrative data identified all NZ residents aged 30-74 years on 31 March 2013 with known ethnicity and country of birth. All participants were described according to ethnicity and country of birth. Pacific participants were also described according to the number of ethnicities they identified. Findings: A total of 2,238,039 NZ residents were included, of whom 117,957 (5·0%) were Pacific. Nearly two-thirds of Pacific peoples (65·7%) were born overseas, ranging from 45·3% (Cook Islands Maori) to 82·7% (Fijian) (Maori 2·3%, non-Maori non-Pacific 28·9%). Among NZ-born Pacific peoples, 46·9% (Samoan) to 81·9% (Fijian) were multi-ethnic; the proportion was much lower for overseas-born Pacific peoples (ranging from 3·7% [Tongan] to 23·9% [Tokelauan]). Interpretation: There is substantial heterogeneity among Pacific peoples in their country of birth and identification with sole or multiple ethnicities. Assumptions regarding homogeneity in the needs of Pacific peoples are not appropriate and government statistics should therefore disaggregate Pacific peoples whenever possible. Funding: Supported by the Health Research Council of New Zealand and a part of Manawataki Fatu Fatu, a programme of research funded by the National Heart Foundation of New Zealand and Healthier Lives - He Oranga Hauora - National Science Challenge of New Zealand.

Herpes zoster vaccine effectiveness against herpes zoster and postherpetic neuralgia in New Zealand: a retrospective cohort study.

Background: Herpes zoster (HZ) and associated complications cause significant burden to older people. A HZ vaccination programme was introduced in Aotearoa New Zealand in April 2018 with a single dose vaccine for those aged 65 years and a four-year catch up for 66-80 year-olds. This study aimed to assess the 'real-world' effectiveness of the zoster vaccine live (ZVL) against HZ and postherpetic neuralgia (PHN). Methods: We conducted a nationwide retrospective matched cohort study from 1 April 2018 to 1 April 2021 using a linked de-identified patient level Ministry of Health data platform. A Cox proportional hazards model was used to estimate ZVL vaccine effectiveness (VE) against HZ and PHN adjusting for covariates. Multiple outcomes were assessed in the primary (hospitalised HZ and PHN - primary diagnosis) and secondary (hospitalised HZ and PHN: primary and secondary diagnosis, community HZ) analyses. A sub-group analysis was carried out in, adults ≥ 65 years old, immunocompromised adults, Maori, and Pacific populations. Findings: A total of 824,142 (274,272 vaccinated with ZVL matched with 549,870 unvaccinated) New Zealand residents were included in the study. The matched population was 93.4% immunocompetent, 52.2% female, 80.2% European (level 1 ethnic codes), and 64.5% were 65-74 years old (mean age = 71.1±5.0). Vaccinated versus unvaccinated incidence of hospitalised HZ was 0.16 vs. 0.31/1,000 person-years and 0.03 vs. 0.08/1000 person-years for PHN. In the primary analysis, the adjusted overall VE against hospitalised HZ and hospitalised PHN was 57.8% (95% CI: 41.1-69.8) and 73.7% (95% CI:14.0-92.0) respectively. In adults ≥ 65 years old, the VE against hospitalised HZ was 54.4% (95% CI: 36.0-67.5) and VE against hospitalised PHN was 75·5% (95% CI: 19.9-92.5). In the secondary analysis, the VE against community HZ was 30.0% (95% CI: 25.6-34.5). The ZVL VE against hospitalised HZ for immunocompromised adults was 51.1% (95% CI: 23.1-69.5), and PHN hospitalisation was 67.6% (95% CI: 9.3-88.4). The VE against HZ hospitalisation for Maori was 45.2% (95% CI: -23.2-75.6) and for Pacific Peoples was 52.2% (95% CI: -40.6 -83·7). Interpretation: ZVL was associated with a reduction in risk of hospitalisation from HZ and PHN in the New Zealand population. Funding: Wellington Doctoral Scholarship awarded to JFM.