Suchergebnisse

ABSTRACTObjectivesPregnant women are the highest priority for seasonal influenza vaccination. Previous research has found maternal immunisation may not only reduce respiratory infections in mothers and infants, but also prevents adverse birth outcomes. Although the vaccine has been offered to pregnant women under the National Immunisation Program since 2009, no population-based study has yet evaluated its impact on neonatal health in Australia.
ApproachWe established a large retrospective cohort of 58,615 births between 2012 and 2013 in Western Australia using data linkage of state-held maternal vaccination records, birth registrations, hospital inpatient records, and midwives notifications. Cox regression models were used to compare the adjusted relative hazard (HR) of adverse birth outcomes and hospital admission for an acute respiratory illness (ARI) by vaccination status.
ResultsIn total, 5,241 (8.9%) of infants were born to vaccinated mothers. Between 2012 and 2013, there were 23.6 ARI admissions per 1,000 infants <6 months and 2.8 ARI admissions per 1,000 pregnant women. Influenza vaccination was associated with a 51% reduction in stillbirth (aHR: 0.49; 95% CI: 0.29-0.84) and a 25% reduction in infant admissions in the first six months of life (aHR: 0.75; 95% CI: 0.56-0.99). Most of the reduction in ARI admission in infants was observed when vaccination occurred in the third trimester (aHR: 0.68; 95% CI: 0.47-0.95).
ConclusionsOur findings support the neonatal health benefits afforded by maternal influenza immunisation and underscore the importance of offering and promoting influenza vaccination to pregnant women. Considering more than 90% of women who choose to be immunised do so to protect their infant, these results could be used to powerfully promote maternal immunisation.

AbstractThe Australian Twin Registry (ATR) has, since the late 1970s, enrolled more than 30,000 pairs of all zygosity types and ages willing to consider participation in approved research studies. Its core functions are the recruitment to, and maintenance of, an up-to-date database containing contact details and baseline information, and the management of fair and equitable access so as to enhance medical and scientific research. The ATR has facilitated more than 430 studies producing 525 peer-reviewed publications using a variety of designs including classic biometrical twin and twin family studies, co-twin control studies, intervention studies, longitudinal studies, and studies of issues relevant specifically to twins. The ATR is supported for 2004 to 2009 by an Australian National Health and Medical Research Council (NHMRC) Enabling Grant, a new form of funding which recognizes the importance of long-term support for shared national resources. New initiatives include: integration with the Western Australian Twin Child Health (WATCH) cohort and the new Western Australian Twin Registry (WATR); foundation of a cohort of mothers and their twin children recruited from the time of diagnosis of the multiple gestation (match); a national Twins Festival run in collaboration with the Australian Multiple Birth Association (AMBA); promotion of the ATR at medical conferences; and fostering an active network of researchers from a range of disciplines and providing financial support for new researchers to attend international twin research workshops. Consistent with its mission statement, the long-term goal of the ATR is to make twin studies a standard component of medical and scientific research.

IntroductionImmunisation coverage is a good measure of immunisation program effectiveness. Coverage of the 3-dose infant schedule in Australia assessed at age 12 months is >90%. Timeliness is an important goal for population immunity, but on-time coverage of the 2-4-6 month schedule and coverage in specific populations is rarely reported.
Objectives and ApproachWe conducted a retrospective population-based cohort study of 1.9 million Australian births, 1996-2012 (approximately 42% of Australia's population). Individual data from state-held birth and perinatal records were combined with Commonwealth-held immunisation and death records, through probabilistic linkage. We assessed on-time coverage across 13 demographic and perinatal characteristics of diphtheria-tetanus-pertussis vaccines (DTP) defined as vaccination 14 days prior to the scheduled due date, to 30 days afterwards.
ResultsOn-time DTP vaccination coverage in non-Aboriginal infants was 88.1% for the 2-month dose, 82.0% for 4-month dose, and 76.7% for 6-month dose; 3-dose coverage was 91.3% when assessed at 12 months. On-time DTP coverage for Aboriginal infants was 77.0%, 66.5%, and 61.0%; 3-dose coverage at 12 months was 79.3%. Appreciable differences in on-time coverage were observed across population subgroups. On-time coverage in non-Aboriginal infants born to mothers with ≥3 previous pregnancies was 62.5% for the 6-month dose (47.9% for Aboriginal infants); up to 23.5% lower than for first-borns. Infants born to mothers who smoked during pregnancy had coverage 8.7-10.3% lower than infants born to non-smoking mothers for the 4- and 6-month dose. A linear relationship was apparent with increasing socio-economic disadvantage and decreasing on-time coverage.
Conclusion/ImplicationsOn-time vaccination coverage of the 2-4-6 month schedule is only 50-60% across specific population subgroups representing a significant avoidable public health risk. Australian Aboriginal infants, multiparous mothers, and those who are socio-economically disadvantaged are key groups most likely to benefit from targeted programs addressing vaccine timeliness.

ABSTRACT
ObjectivesAcute lower respiratory infections (ALRI) such as bronchiolitis, pneumonia and influenza are a common cause of childhood morbidity. The relative importance of individual respiratory viruses associated with these infections may fluctuate in different populations. Knowledge of the aetiology of ALRI is important so that preventive strategies, such as vaccination, may be targeted appropriately. We sought to describe the virus-specific burden of ALRI in children born in Western Australia (WA).
ApproachWe identified a birth cohort of children born in WA from 1996 to 2012. ALRI-coded hospital admissions and routine laboratory data regarding the detection of respiratory viruses pertaining to these children were extracted and linked through the WA Data Linkage Unit. Hospitalisation and laboratory data were restricted to Jan 2000 to Jun 2013 as laboratory data were only available for this period.
Repeat hospital admissions for ALRI within 14 days of each other were collapsed into the same episode of infection. Virus detection was defined as detection via culture, immunofluorescence or molecular methods from a respiratory sample 48 hours pre- or post-hospitalisation. We estimated the proportion of ALRI episodes in children aged up to 17 years with a laboratory test recorded and identified the viruses detected. Using person-time-at-risk as the denominator, we calculated the virus-specific rates of ALRI in 2000-2012 in the birth cohort.
ResultsOf 469,589 children born 1996-2012, 7.0% were admitted to hospital at least once for ALRI between Jan 2000 and Jun 2013. Bronchiolitis and pneumonia were the most common diagnoses, collectively accounting for 73.3% (n=32,815) of all ALRI episodes.
45.4% of ALRI episodes (n=20,323) in children aged 0-17 years linked to a laboratory test record. Of those with a laboratory record, 60.0% tested positive for one or more viruses, most commonly respiratory syncytial virus (RSV; n=7671). Of those with at least 1 virus detected, 4.7% had 2 or more viruses detected, with RSV-adenovirus being the most common viral pair.
Among children aged under 5 years, rates of virus-related ALRI hospitalisation were highest in children aged 1-2 months (37.2 per 1000 child-years), corresponding to the peak in RSV-related hospitalisations (30.6 per 1000 child-years). By contrast, rates of adenovirus-related hospitalisations were highest in children aged 6-11 months (1.7 per 1000 child-years).
ConclusionThis study demonstrates the power of using linked data to assess the virus-specific burden of ALRI in a population of children. Future work will focus on viral-viral coinfection and its impact on clinical outcomes.

IntroductionRespiratory Syncytial Virus (RSV) causes considerable morbidity in children. RSV vaccines are in development, but the only current preventive measure is immunoprophylaxis with monoclonal antibody, palivizumab. Australia has no uniform palivizumab guidelines. In Western Australia palivizumab is licensed for use in high risk children but compliance and effectiveness is unknown.
Objectives and ApproachWe conducted a retrospective cohort study using palivizumab data from multiple pharmacy dispensing datasets which had been linked with routine laboratory, hospital morbidity, emergency department presentations, deaths and perinatal data for a cohort of infants admitted to Level 3 Neonatal Intensive Care Units (NICU) between 2002 and 2013. We identified palivizumab eligible infants as those who were extremely premature (<28 weeks gestation) with bronchopulmonary dysplasia and/or who identified as Indigenous and were NICU inpatients during the annual winter RSV season (May-October). We describe the use of palivizumab in infants that did and did not fit the eligibility criteria.
ResultsThe NICU cohort included 24,367 infants, of which 1754 had at least 1 RSV-confirmed infection before age 5 years. A total of 686 (2.8%) cohort infants were eligible for palivizumab. Palivizumab dispensing data were amalgamated from 5 pharmacy datasets. Overall, 173 of the palivizumab eligible infants (25.2%) had at least 1 palivizumab dose (27% 1 dose, 34% 2 doses, 28% 3 doses and 11% 4 or more doses). From 2011 when palivizumab guidelines were formalised, 143 (75%) had at least 1 dose. Compliance with at least 1 palivizumab dose was highest in 2011 (84.9%). From 2002-2013, 98 infants were given palivizumab outside eligibility criteria (33% 1 dose, 33% 2 doses, 34% 3 or more doses) with annual use increasing since 2008.
Conclusion/ImplicationsThis is the first time pharmacy dispensing data have been linked to other datasets to measure use and effectiveness. Compliance with palivizumab guidelines was high from 2011. These data will be used to measure the effectiveness of palivizumab against RSV-confirmed infections and respiratory infection-related hospitalisations up to age 5 years.

ABSTRACTObjectivesAustralia's Childhood Immunisation Register (ACIR) is one of only a handful of national immunisation registers world-wide. We have, for the first time, linked the ACIR to other health datasets to measure the real-world impact of Australia's immunisation program. In this study, we aimed to assess the population-based effectiveness of the 3-dose infant pneumococcal vaccination program (due at 2, 4, and 6 months) against invasive pneumococcal disease caused by the 7 vaccine specific serotypes. The 7-valent pneumococcal conjugate vaccine (PCV7) has been available since 2001 and a funded universal program started in 2005 (with a switch to 13-valent PCV in 2011). ApproachVaccination records from ACIR, death records, and invasive pneumococcal disease notifications for 2001-2013 were individually linked for 1.37 million children born in 2001-2012 in two Australian states (Western Australia and New South Wales). A Cox proportional hazards model (adjusting for sex, Indigenous status and year of birth) was used to estimate the hazard ratio for invasive pneumococcal disease in vaccinated compared to unvaccinated children less than 2 years old. The per cent of disease prevented by vaccination, or vaccine effectiveness, was calculated as (1-adjusted hazard ratio) x 100%. ResultsFrom 2005, vaccination coverage with dose 3 of the pneumococcal vaccine was steady at ~91% in eligible cohorts. Between 2001 and 2013, there were 468 notifications of invasive pneumococcal disease caused by the 7 vaccine specific serotypes during 2.66 million person years of observation; only 39 (8.3%) of these cases occurred after the universal program was implemented. Vaccine effectiveness against invasive pneumococcal disease caused by the 7 vaccine specific serotypes for 1, 2 and 3 doses of the pneumococcal vaccine was 68% (95%CI: 44-89%), 93% (81-97%), and 92% (95%CI: 86-93%), respectively. ConclusionThis is the first study to link Australia's national immunisation register and measure population-based vaccine effectiveness. The study provides robust evidence of the effectiveness of at least 2 doses of pneumococcal vaccine against vaccine serotype specific infection using a 3 dose infant schedule.

ABSTRACT
ObjectiveImmunisation remains one of the most important public health interventions. However, linkage of population-based immunisation registers to perinatal and health outcome datasets to evaluate immunisation programs is limited. We have conducted the first-ever linkages of immunisation records from Australia's Childhood Immunisation Register (ACIR) for the purposes of evaluating Australia's unique national immunisation program. As an initial outcome of our linkage study we present estimates of pneumococcal conjugate vaccine (PCV) coverage for the 3rd dose assessed at 12 months of age in extremely preterm children (gestational age <28 weeks), in whom a funded vaccination program was established in 2001 prior to a universal funded program for all children in 2005.
ApproachIndividual immunisation records from ACIR, hospital admissions, deaths and infectious diseases notifications were linked to perinatal records for a cohort of births from 1996 to 2012 in two Australian states. Three separate data linkage units were involved in the process with varying procedures for linkage. The perinatal datasets were used to identify extremely preterm children.
ResultsThe birth cohort for the study included 1,958,537 live births in New South Wales (1,492,399) and Western Australia (461,620). Linkage weights based on sensitivity and positive predictive value of >99% were used to identify immunisation records from ACIR to link to the birth cohort. A unique scrambled pin on ACIR was used to link immunisation records to birth cohort datasets. The final cohort consisted of 1,954,019 children with 95.5% linking to at least 1 ACIR record from a total of >26.6 million ACIR records. In 2001, coverage of the 3rd dose of PCV in extremely preterm children was 0.9% and increased to 69.1% in 2004 (overall coverage 2001-2004: 25.3%). From 2005 to 2012, coverage increased to an average of 89.7%.
ConclusionThese are the first results of cross-jurisdictional linkages of immunisation records to state-based administrative datasets in Australia. This process has identified some improvements that are needed to streamline future linkage projects of this scale. Linkage of perinatal datasets to ACIR has enabled us to assess the first-ever coverage estimates in specific medically at-risk population subgroups. Future analyses will focus on the predictors and timeliness of vaccination coverage and population based estimates of vaccine effectiveness.

AbstractObjectivesAn asbestos job-exposure matrix (AsbJEM) has been developed to systematically and cost-effectively evaluate occupational exposures in population-based studies. The primary aim of this study was to examine the accuracy of the AsbJEM in determining exposure–response relationships between asbestos exposure estimates and malignant mesothelioma (MM) incidence (indirect validation). The secondary aim was to investigate whether the assumptions used in the development of the original AsbJEM provided accurate asbestos exposure estimates.MethodsThe study population consisted of participants in an annual health surveillance program, who had at least 3-month occupational asbestos exposure. Calculated asbestos exposure indices included cumulative asbestos exposure and the average exposure intensity, estimated using the AsbJEM and duration of employment. Asbestos and MM exposure–response relationships were compared between the original AsbJEM and its variations based on manipulations of the intensity, duration and frequency of exposure. Twenty-four exposure estimates were calculated for both cumulative asbestos exposure and the average exposure intensity using three exposure intensities (50th, 75th and 90th percentile of the range of mode exposure), four peak durations (15, 30, 60 and 120 min) and two patterns of peak frequency (original and doubled). Cox proportional hazards models were used to describe the associations between MM incidence and each of the cumulative and average intensity estimates.ResultsData were collected from 1602 male participants. Of these, 40 developed MM during the study period. There were significant associations between MM incidence and both cumulative and average exposure intensity for all estimates. The strongest association, based on the regression-coefficient from the models, was found for the 50th percentile of mode exposure, 15-min peak duration and the doubled frequency of peak exposure. Using these assumptions, the hazard ratios for mesothelioma were 1 (reference), 1.91, 3.24 and 5.37 for the quartiles of cumulative asbestos exposure and 1 (reference), 1.84, 2.31 and 4.40 for the quartiles of the average exposure intensity, respectively.ConclusionThe well-known positive exposure–response relationship between MM incidence and both estimated cumulative asbestos exposure and average exposure intensity was confirmed. The strongest relationship was found when the frequency of peak exposure in the AsbJEM was doubled from the originally published estimates.

AbstractA common chemical exposure in alumina refining is caustic mist. Although recognized as a strong airways irritant, little is known of the chronic respiratory effects of caustic mist in alumina refining. A suitable metric for caustic mist exposure assessment in alumina refining for epidemiological purposes has not been identified. Peak exposure is likely to be important, but is difficult to assess in epidemiological studies. In this study, we investigate the respiratory effects of caustic mist in an inception cohort (n = 416) of alumina refinery workers and describe the development and use of a peak exposure metric for caustic mist. We then compare the results with a metric based on duration of exposure. Participants were interviewed annually about respiratory symptoms and had a lung function test. Job history data were collected from each interview and levels of caustic mist were measured periodically by air monitoring. We found a weak association between the caustic mist peak exposure metric and reported cough (P for linear trend = 0.079) with the highest peak exposure group odds ratio = 2.32 (95% confidence interval: 1.27, 4.22). For lung function, we found declines in the forced expiratory volume in 1 second and forced vital capacity for changes in annual and absolute lung function for both metrics of exposure, but only the ratio of absolute lung function was statistically associated with an increasing duration of caustic exposure (P for linear trend = 0.011). In this cohort, we did not observe an association with respiratory symptoms or consistent decrements in lung function. There was little difference between the exposure metrics used for investigation of the chronic effects from caustic mist.

IntroductionSeveral countries have developed national immunisation registers, but only the Nordic countrieshave linked their registers to other health data in order to comprehensively evaluate the 'real world'effectiveness of vaccines. Nordic countries can link datasets deterministically using the nationalperson identifier, but most countries, including Australia, don't have such an identifier to enablethis type of linkage.
ObjectivesTo describe the process for assembling a linked study cohort that will enable the conduct ofpopulation-based studies related to immunisation and immunisation policy.
MethodsNational death and immunisation databases along with state health data (notifications of vaccinepreventable diseases, perinatal data, hospital admissions and emergency department presentations)up until December 2013 were probabilistically linked (using demographic details) for children bornbetween 1996 and 2012 in two states: Western Australia and New South Wales (42% of Australia'spopulation, combined).
ResultsAfter exclusions there were 1.95 million children in the study cohort (live born children withboth a birth and perinatal record which represents 97.5% of all live births in the state perinataldata collections - our source population) and 18.0 million person years of follow up (mean: 9.2years per child). The characteristics of children in the cohort were generally similar to those onlyincluded in state perinatal databases and outcome measures were in keeping with expected figuresfrom unlinked data sources. However, the lack of a dynamic national population register meantimmigrants could not be included.
ConclusionsWe have been able to develop a similarly comprehensive system to the Nordic countries based onprobabilistic linkage methods. Our experience should provide encouragement to other countrieswith national immunisation registers looking to establish similar systems.

BACKGROUND: Hospitalisation with skin infection in Western Australian (WA) Aboriginal children is common, with the highest rates in infants and children from remote WA. We aimed to quantify infant, maternal, and sociodemographic risk factors for skin infection hospitalization in WA children, focusing on Aboriginal children aged <17 years. METHODS: We conducted a retrospective population-based cohort study with linked perinatal and hospitalization data on WA-born children (1996–2012), of whom 31,348 (6.7%) were Aboriginal. We used Cox regression to calculate adjusted hazard ratios and associated population attributable fractions (PAFs) for perinatal factors attributed to the first hospitalization with skin infection. To identify specific risk factors for early-onset infection, we further restricted the cohort to infants aged <1 year. RESULTS: Overall, 5,439 (17.4%) Aboriginal and 6,750 (1.5%) non-Aboriginal children were hospitalized at least once with a skin infection. Aboriginal infants aged <1 year had the highest skin infection hospitalization rate (63.2/1,000 child-years). The strongest risk factors in Aboriginal children aged <17 years were socio-economic disadvantage, very remote location at birth and multi-parity (≥3 previous pregnancies) accounting for 24%, 23% and 15% of skin infection hospitalizations, respectively. Other risk factors included maternal age <20 years, maternal smoking during pregnancy and low birthweight. CONCLUSION: We have quantified the relative influence of perinatal risk factors associated with skin infection hospitalizations in WA children, providing measures indicating which factors have the potential to reduce the most hospitalizations. Our evidence supports existing calls for substantial government investment in addressing underlying social and environmental barriers to healthy skin in WA Aboriginal children but also identifies potential areas to target health promotion messaging at individuals/families on maternal smoking during pregnancy and skin hygiene for ...