Hearing loss in Australian First Nations children at 6-monthly assessments from age 12 to 36 months: Secondary outcomes from randomised controlled trials of novel pneumococcal conjugate vaccine schedules.

BACKGROUND: In Australian remote communities, First Nations children with otitis media (OM)-related hearing loss are disproportionately at risk of developmental delay and poor school performance, compared to those with normal hearing. Our objective was to compare OM-related hearing loss in children randomised to one of 2 pneumococcal conjugate vaccine (PCV) formulations. METHODS AND FINDINGS: In 2 sequential parallel, open-label, randomised controlled trials (the PREVIX trials), eligible infants were first allocated 1:1:1 at age 28 to 38 days to standard or mixed PCV schedules, then at age 12 months to PCV13 (13-valent pneumococcal conjugate vaccine, +P) or PHiD-CV10 (10-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine, +S) (1:1). Here, we report prevalence and level of hearing loss outcomes in the +P and +S groups at 6-monthly scheduled assessments from age 12 to 36 months. From March 2013 to September 2018, 261 infants were enrolled and 461 hearing assessments were performed. Prevalence of hearing loss was 78% (25/32) in the +P group and 71% (20/28) in the +S group at baseline, declining to 52% (28/54) in the +P groups and 56% (33/59) in the +S group at age 36 months. At primary endpoint age 18 months, prevalence of moderate (disabling) hearing loss was 21% (9/42) in the +P group and 41% (20/49) in the +S group (difference -19%; (95% confidence interval (CI) [-38, -1], p = 0.07) and prevalence of no hearing loss was 36% (15/42) in the +P group and 16% (8/49) in the +S group (difference 19%; (95% CI [2, 37], p = 0.05). At subsequent time points, prevalence of moderate hearing loss remained lower in the +P group: differences -3%; (95% CI [-23, 18], p = 1.00 at age 24 months), -12%; (95% CI [-30, 6], p = 0.29 at age 30 months), and -9%; (95% CI [-23, 5], p = 0.25 at age 36 months). A major limitation was the small sample size, hence low power to reach statistical significance, thereby reducing confidence in the effect size. CONCLUSIONS: In this study, we observed a high prevalence and persistence of moderate (disabling) hearing loss throughout early childhood. We found a lower prevalence of moderate hearing loss and correspondingly higher prevalence of no hearing loss in the +P group, which may have substantial benefits for high-risk children, their families, and society, but warrant further investigation. TRIAL REGISTRATION: ClinicalTrials.gov NCT01735084 and NCT01174849.

The effectiveness of maternal pertussis vaccination for protecting Aboriginal and Torres Strait Islander infants against infection, 2012-2017: a retrospective cohort study.

OBJECTIVES: To evaluate the effectiveness of maternal pertussis vaccination for preventing pertussis infections in Aboriginal and Torres Strait Islander infants under seven months of age. STUDY DESIGN: Retrospective cohort study; analysis of linked administrative health data. SETTING, PARTICIPANTS: Mother-infant cohort (Links2HealthierBubs) including all pregnant women who gave birth to live infants (gestational age ≥ 20 weeks, birthweight ≥ 400 g) in the Northern Territory, Queensland, and Western Australia during 1 January 2012 - 31 December 2017. MAIN OUTCOME MEASURES: Proportions of women vaccinated against pertussis during pregnancy, rates of pertussis infections among infants under seven months of age, and estimated effectiveness of maternal vaccination for protecting infants against pertussis infection, each by Indigenous status. RESULTS: Of the 19 892 Aboriginal and Torres Strait Islander women who gave birth to live infants during 2012-2017, 7398 (37.2%) received pertussis vaccine doses during their pregnancy, as had 137 034 of 259 526 non-Indigenous women (52.8%; Indigenous v non-Indigenous: adjusted odds ratio, 0.66; 95% confidence interval [CI], 0.62-0.70). The annual incidence of notified pertussis infections in non-Indigenous infants declined from 16.8 (95% CI, 9.9-29) in 2012 to 1.4 (95% CI, 0.3-8.0) cases per 10 000 births in 2017; among Aboriginal and Torres Strait Islander infants, it declined from 47.6 (95% CI, 16.2-139) to 38.6 (95% CI, 10.6-140) cases per 10 000 births. The effectiveness of maternal vaccination for protecting non-Indigenous infants under seven months of age against pertussis infection during 2014-17 was 68.2% (95% CI, 51.8-79.0%); protection of Aboriginal and Torres Strait Islander infants was not statistically significant (36.1%; 95% CI, -41.3% to 71.1%). CONCLUSIONS: During 2015-17, maternal pertussis vaccination did not protect Aboriginal and Torres Strait Islander infants in the NT, Queensland, and WA against infection. Increasing the pertussis vaccination rate among pregnant Aboriginal and Torres Strait Islander women requires culturally appropriate, innovative strategies co-designed in partnership with Indigenous organisations and communities.

Maternal Pertussis Vaccination, Infant Immunization, and Risk of Pertussis.

OBJECTIVES: Following the introduction of jurisdictional maternal pertussis vaccination programs in Australia, we estimated maternal vaccine effectiveness (VE) and whether maternal pertussis vaccination modified the effectiveness of the first 3 primary doses of pertussis-containing vaccines. METHODS: We conducted a population-based cohort study of 279 418 mother-infant pairs using probabilistic linkage of administrative health records in 3 Australian jurisdictions. Infants were maternally vaccinated if their mother had a documented pertussis vaccination ≥14 days before birth. Jurisdictional immunization records were used to identify receipt of the first 3 infant doses of pertussis-containing vaccines. Infant pertussis infections were identified using notifiable disease records. VE was estimated using Cox proportional hazard models. RESULTS: Pertussis was administered during 51.7% (n = 144 429/279 418) of pregnancies, predominantly at 28-31 weeks' gestation. VE of maternal pertussis vaccination declined from 70.4% (95% confidence interval [CI], 50.5-82.3) among infants <2 months old to 43.3% (95% CI, 6.8-65.6) among infants 7-8 months old and was not significant after 8 months of age. Although we observed slightly lower VE point estimates for the third dose of infant pertussis vaccine among maternally vaccinated compared with unvaccinated infants (76.5% vs 92.9%, P = .002), we did not observe higher rates of pertussis infection (hazard ratio, 0.70; 95% CI, 0.61-3.39). CONCLUSIONS: Pertussis vaccination near 28 weeks' gestation was associated with lower risk of infection among infants through 8 months of age. Although there was some evidence of lower effectiveness of infant vaccination among maternally vaccinated infants, this did not appear to translate to greater risk of disease.

Extracellular traps are evident in Romanowsky-stained smears of bronchoalveolar lavage from children with non-cystic fibrosis bronchiectasis.

BACKGROUND AND OBJECTIVE: The importance of extracellular traps (ETs) in chronic respiratory conditions is increasingly recognized but their role in paediatric bronchiectasis is poorly understood. The specialized techniques currently required to study ETs preclude routine clinical use. A simple and cost-effective ETs detection method is needed to support diagnostic applications. We aimed to determine whether ETs could be detected using light microscopy-based assessment of Romanowsky-stained bronchoalveolar lavage (BAL) slides from children with bronchiectasis, and whether the ETs cellular origin could be determined. METHODS: Archived Romanowsky-stained BAL slides from a cross-sectional study of children with bronchiectasis were examined for ETs using light microscopy. The cellular origin of individual ETs was determined based on morphology and physical contact with surrounding cell(s). RESULTS: ETs were observed in 78.7% (70/89) of BAL slides with neutrophil (NETs), macrophage (METs), eosinophil (EETs) and lymphocyte (LETs) ETs observed in 32.6%, 51.7%, 4.5% and 9%, respectively. ETs of indeterminate cellular origin were present in 59.6% of slides. Identifiable and indeterminate ETs were co-detected in 43.8% of slides. CONCLUSION: BAL from children with bronchiectasis commonly contains multiple ET types that are detectable using Romanowsky-stained slides. While specialist techniques remain necessary to determining the cellular origin of all ETs, screening of Romanowsky-stained slides presents a cost-effective method that is well-suited to diagnostic settings. Our findings support further research to determine whether ETs can be used to define respiratory endotypes and to understand whether ETs-specific therapies may be required to resolve airway inflammation among children with bronchiectasis.

Randomised controlled trial of perinatal vitamin D supplementation to prevent early-onset acute respiratory infections among Australian First Nations children: the 'D-Kids' study protocol.

INTRODUCTION: Globally, acute respiratory infections (ARIs) are a leading cause of childhood morbidity and mortality. While ARI-related mortality is low in Australia, First Nations infants are hospitalised with ARIs up to nine times more often than their non-First Nations counterparts. The gap is widest in the Northern Territory (NT) where rates of both acute and chronic respiratory infection are among the highest reported in the world. Vitamin D deficiency is common among NT First Nations neonates and associated with an increased risk of ARI hospitalisation. We hypothesise that perinatal vitamin D supplementation will reduce the risk of ARI in the first year of life. METHODS AND ANALYSIS: 'D-Kids' is a parallel (1:1), double-blind (allocation concealed), randomised placebo-controlled trial conducted among NT First Nations mother-infant pairs. Pregnant women and their babies (n=314) receive either vitamin D or placebo. Women receive 14 000 IU/week or placebo from 28 to 34 weeks gestation until birth and babies receive 4200 IU/week or placebo from birth until age 4 months. The primary outcome is the incidence of ARI episodes receiving medical attention in the first year of life. Secondary outcomes include circulating vitamin D level and nasal pathogen prevalence. Tertiary outcomes include infant immune cell phenotypes and challenge responses. Blood, nasal swabs, breast milk and saliva are collected longitudinally across four study visits: enrolment, birth, infant age 4 and 12 months. The sample size provides 90% power to detect a 27.5% relative reduction in new ARI episodes between groups. ETHICS AND DISSEMINATION: This trial is approved by the NT Human Research Ethics Committee (2018-3160). Study outcomes will be disseminated to participant families, communities, local policy-makers, the broader research and clinical community via written and oral reports, education workshops, peer-reviewed journals, national and international conferences. TRIAL REGISTRATION NUMBER: ACTRN12618001174279.

Inequity of antenatal influenza and pertussis vaccine coverage in Australia: the Links2HealthierBubs record linkage cohort study, 2012-2017.

BACKGROUND: Pregnancy and early infancy are increased risk periods for severe adverse effects of respiratory infections. Aboriginal and/or Torres Strait Islander (respectfully referred to as First Nations) women and children in Australia bear a disproportionately higher burden of respiratory diseases compared to non-Indigenous women and infants. Influenza vaccines and whooping cough (pertussis) vaccines are recommended and free in every Australian pregnancy to combat these infections. We aimed to assess the equity of influenza and/or pertussis vaccination in pregnancy for three priority groups in Australia: First Nations women; women from culturally and linguistically diverse (CALD) backgrounds; and women living in remote areas or socio-economic disadvantage. METHODS: We conducted individual record linkage of Perinatal Data Collections with immunisation registers/databases between 2012 and 2017. Analysis included generalised linear mixed model, log-binomial regression with a random intercept for the unique maternal identifier to account for clustering, presented as prevalence ratios (PR) and 95% compatibility intervals (95%CI). RESULTS: There were 445,590 individual women in the final cohort. Compared with other Australian women (n = 322,848), First Nations women (n = 29,181) were less likely to have received both recommended antenatal vaccines (PR 0.69, 95% CI 0.67-0.71) whereas women from CALD backgrounds (n = 93,561) were more likely to have (PR 1.16, 95% CI 1.10-1.13). Women living in remote areas were less likely to have received both vaccines (PR 0.75, 95% CI 0.72-0.78), and women living in the highest areas of advantage were more likely to have received both vaccines (PR 1.44, 95% CI 1.40-1.48). CONCLUSIONS: Compared to other groups, First Nations Australian families, those living in remote areas and/or families from lower socio-economic backgrounds did not receive recommended vaccinations during pregnancy that are the benchmark of equitable healthcare. Addressing these barriers must remain a core priority for Australian health care systems and vaccine providers. An extension of this cohort is necessary to reassess these study findings.

Can non-typeable Haemophilus influenzae carriage surveillance data infer antimicrobial resistance associated with otitis media?

Importance: In remote communities of the Northern Territory, Australia, children experience high rates of otitis media (OM), commonly caused by non-typeable Haemophilus influenzae (NTHi). Few data exist on antibiotic susceptibility of NTHi from OM. Objective: To determine whether population-level nasopharyngeal NTHi antibiotic susceptibility data could inform antibiotic treatment for OM. Methods: NTHi isolates (n = 92) collected from ear discharge between 2003 and 2013 were selected to time- and age-match NTHi isolates from the nasopharyngeal carriage (n = 95). Antimicrobial susceptibility were tested. Phylogenomic trees and a genome-wide association study (GWAS) were performed to determine the similarity of nasopharyngeal and ear isolates at a population level. Results: Among 174 NTHi isolates available for antimicrobial susceptibility testing, 10.3% (18/174) were resistant to ampicillin and 9.2% (16/174) were resistant to trimethoprim-sulfamethoxazole. Small numbers of isolates (≤3) were resistant to tetracycline, chloramphenicol, or amoxicillin-clavulanic acid. There was no statistical difference in the proportion of ampicillin-resistant (P = 0.11) or trimethoprim-sulfamethoxazole-resistant isolates (P = 0.70) between ear discharge and nasopharynx-derived NTHi isolates. Three multi-drug resistant NTHi isolates were identified. Phylogenomic trees showed no clustering of 187 Haemophilus influenzae isolates based on anatomical niche (nasopharynx or ear discharge), and no genetic variations that distinguished NTHi derived from ear discharge and nasopharyngeal carriage were evident in the GWAS. Interpretation: In this population-level study, nasopharyngeal and ear discharge isolates did not represent distinct microbial populations. These results support tracking of population-level nasopharyngeal NTHi antibiotic resistance patterns to inform clinical management of OM in this population.

Timing and temporal trends of influenza and pertussis vaccinations during pregnancy in three Australian jurisdictions: The Links2HealthierBubs population-based linked cohort study, 2012-2017.

BACKGROUND: Antenatal inactivated influenza (IIV) and pertussis-containing vaccines (dTpa) offer protection against severe respiratory infections for pregnant women and infants <6 months of age. Both vaccines are recommended in pregnancy; however, little is known about temporal or jurisdictional trends and predictors of uptake. AIMS: To identify gaps and predictors of IIV and/or dTpa vaccinations in Australian pregnancies from 2012 to 2017. MATERIALS AND METHODS: We conducted a probabilistically linked, multi-jurisdictional population-based cohort study, drawing from perinatal data collections and immunisation databases. We used a generalised linear mixed model with a random effect term to account for clustering of multiple pregnancies within mothers, to calculate vaccination uptake, and identify predictors of uptake by maternal demographic, pregnancy, and health characteristics. RESULTS: Of 591 868 unique pregnancies, IIV uptake was 15%, dTpa 27% and 12% received both vaccines. Pertussis vaccinations in First Nations pregnancies were 20% lower than non-Indigenous pregnancies; dTpa was strongly associated with IIV uptake (risk ratio (RR): 8.60, 95% CI 8.48-8.73). This trend was temporally and jurisdictionally consistent. First Nations women were more likely to have had IIV in pregnancy before the introduction of dTpa in the pregnancy program: (RR: 1.48, 95% CI 1.40-1.57), but less likely after dTpa implementation (RR: 0.78, 95% CI 0.76-0.80). CONCLUSIONS: Inequity in vaccine uptake between First Nations and non-Indigenous pregnancies, and dismal rates of vaccination in pregnancy overall need urgent review, particularly before the next influenza pandemic or pertussis outbreak. If antenatal dTpa is driving IIV uptake, changes in antenatal healthcare practices are needed to ensure vaccines are offered equitably and optimally to protect against infection.

The Respiratory Microbiome in Paediatric Chronic Wet Cough: What Is Known and Future Directions.

Chronic wet cough for longer than 4 weeks is a hallmark of chronic suppurative lung diseases (CSLD), including protracted bacterial bronchitis (PBB), and bronchiectasis in children. Severe lower respiratory infection early in life is a major risk factor of PBB and paediatric bronchiectasis. In these conditions, failure to clear an underlying endobronchial infection is hypothesised to drive ongoing inflammation and progressive tissue damage that culminates in irreversible bronchiectasis. Historically, the microbiology of paediatric chronic wet cough has been defined by culture-based studies focused on the detection and eradication of specific bacterial pathogens. Various 'omics technologies now allow for a more nuanced investigation of respiratory pathobiology and are enabling development of endotype-based models of care. Recent years have seen substantial advances in defining respiratory endotypes among adults with CSLD; however, less is understood about diseases affecting children. In this review, we explore the current understanding of the airway microbiome among children with chronic wet cough related to the PBB-bronchiectasis diagnostic continuum. We explore concepts emerging from the gut-lung axis and multi-omic studies that are expected to influence PBB and bronchiectasis endotyping efforts. We also consider how our evolving understanding of the airway microbiome is translating to new approaches in chronic wet cough diagnostics and treatments.

Evidence of maternal transfer of antigen-specific antibodies in serum and breast milk to infants at high-risk of S. pneumoniae and H. influenzae disease.

Introduction: Children in low-mid income countries, and First Nations children in high-income countries, experience disproportionately high rates of Streptococcus pneumoniae and Haemophilus influenzae infections and diseases including pneumonia and otitis media. We previously observed that infants from Papua New Guinea had no evidence of waning maternal immunity for H. influenzae-specific antibodies. In this study, we assessed S. pneumoniae and H. influenzae antibody titres in Australian First Nation mothers and infants to determine antigen-specific antibody ontogenies and whether H. influenzae antibody titres in infants were due to low maternal antibody titres or lack of placental transfer. Methods: Breast milk, infant nasopharyngeal swabs and ear assessment data were collected 1-, 2-, 7-months post-birth as well as maternal, cord and 7-month-old infant sera, from 85 Australian Aboriginal and Torres Strait Islander mother-infant pairs. Serum IgG and breast milk IgG and IgA antibody titres to S. pneumoniae antigens (PspA1, PspA2, CbpA, Ply) and H. influenzae antigens (PD, ChimV4, OMP26, rsPilA) were measured. Results: IgG titres in maternal and cord sera were similar for all antigens, except Ply (higher in cord; p=0.004). Sera IgG titres at 7-months of age were lower than cord sera IgG titres for all S. pneumoniae antigens (p<0.001). Infant sera IgG titres were higher than cord sera for H. influenzae PD (p=0.029), similar for OMP26 (p=0.817) and rsPilA (p=0.290), and lower for ChimV4 (p=0.004). Breast milk titres were similar for all antigens at 1, 2 and 7-months except OMP26 IgA (lower at 7-months than 1-month; p=0.035), PspA2 IgG (p=0.012) and Ply IgG that increased by 7-months (p=0.032). One third of infants carried nontypeable Haemophilus influenzae (NTHi), 45% carried S. pneumoniae and 52% had otitis media (OM) observed at least once over the 7-months. 73% of infants who carried either S. pneumoniae or NTHi, also had otitis media observed. Conclusions: Similarities between maternal and cord IgG titres, and absence of waning, support a lack of maternal H. influenzae IgG antibodies available for cross-placental transfer. Increased maternal anti-PD IgG could offer some protection from early carriage with NTHi, and maternal immunisation strategies should be considered for passive-active immunisation of infants to protect against S. pneumoniae and H. influenzae diseases. Trial registration: ClinicalTrials.gov NCT00714064 and NCT00310349.

Prevalence and subtyping of biofilms present in bronchoalveolar lavage from children with protracted bacterial bronchitis or non-cystic fibrosis bronchiectasis: a cross-sectional study.

BACKGROUND: Lower airway biofilms are hypothesised to contribute to poor treatment outcomes among children with chronic lung disease; however, data are scarce. We aimed to determine the presence and prevalence of biofilm in bronchoalveolar lavage from children with protracted bacterial bronchitis (PBB) or bronchiectasis; whether biofilm was associated with signs of lower airway infection; and whether biofilms were consistent with an upper or lower airway origin. METHODS: In this cross-sectional study, fluorescent microscopy techniques were used to detect biofilm in archived bronchoalveolar lavage specimens from a paediatric cohort (age <18 years) with PBB or bronchiectasis who were prospectively recruited to observational studies of chronic cough at Royal Children's Hospital (Brisbane, Australia) or Royal Darwin Hospital (Darwin, Australia). Children with cystic fibrosis were excluded. Lower airway infection was defined as bronchoalveolar lavage neutrophil percentage of 15% or more, or a culture of a bacterial pathogen at 104 colony-forming units per mL or more, or both. Biofilms were subtyped as either of lower airway origin (unrelated to squamous epithelial cells) or of upper airway origin (observed in close association with squamous epithelial cells). Bronchoalveolar lavages were considered contaminated with upper airway secretions if the squamous cell proportion was more than ten cells per 1000 nucleated cells (>1%). Primary outcomes were the prevalence of each biofilm subtype among children with PBB compared with children with bronchiectasis. Secondary outcomes were the prevalence of each biofilm subtype among children with signs of lower airway infection compared to children without. FINDINGS: Biofilm testing was performed on 144 bronchoalveolar lavage specimens collected between Jan 1, 2011, and Dec 16, 2014, and preserved at -80°C before biofilm testing (69 children with PBB from Brisbane and 75 children with bronchiectasis from Darwin). The prevalence of lower airway biofilms (unrelated to squamous epithelial cells) was similar among the children with PBB (25 [36%] of 69) and children with bronchiectasis (31 [41%] of 75; odds ratio [OR] 1·24, 95% CI 0·63-2·43), but higher among children with signs of lower airway infection (46 [48%] of 95) than children without (eight [19%] of 43; OR 4·11, 95% CI 1·73-9·78), irrespective of the underlying diagnosis. By contrast, upper airway biofilms (associated with squamous epithelial cells) were more prevalent among children with bronchiectasis (32 [43%] of 75) than children with PBB (16 [23%] of 69; OR 2·47, 95% CI 1·20-5·08) and were unrelated to lower airway infection. Upper airway contamination was uncommon (eight [11%] of 71) and was not evident in 23 (79%) of 29 bronchoalveolar lavages that were positive for upper airway biofilms. INTERPRETATION: Lower airway biofilms are prevalent, but not ubiquitous, in bronchoalveolar lavage from children with PBB or bronchiectasis, suggesting anti-biofilm therapies might be beneficial for some children. Detection of upper airway biofilms in bronchoalveolar lavage that did not have signs of contamination suggests that microaspiration might be important in some children. Specimen quality measures are recommended for future studies to account for the presence of upper airway biofilms. FUNDING: Financial Markets for Children Project Grant, National Health and Medical Research Council of Australia, Rebecca L Cooper Medical Research Foundation, Queensland Children's Hospital Foundation, and BrightSpark Foundation.

National predictors of influenza vaccine uptake in pregnancy: the FluMum prospective cohort study, Australia, 2012-2015.

OBJECTIVE: Ascertain predictors of inactivated influenza vaccine (IIV) uptake in pregnancy in mother-infant pairs from six Australian sites over four consecutive influenza seasons (2012-2015). METHODS: Prospective observational cohort study calculating proportions of unvaccinated and vaccinated pregnancies. Multivariable logistic regression calculating adjusted odds ratios (aOR) and 95% confidence intervals (95%CI) to determine demographic, pregnancy and birth characteristics as predictors of IIV uptake in pregnancy. RESULTS: Uptake of IIV was 36% (n=3,651/9,878) with only 3-4% during the first trimester. Validation of IIV receipt was obtained for 77% of vaccinated participants. Predictors of IIV uptake in pregnancy were: healthcare provider recommendation to have IIV during pregnancy (aOR 7.04 [95%CI 5.83-8.50]): GP (aOR 4.12 [95%CI 3.43-4.98]), obstetrician (aOR 4.41 [95%CI 3.45-5.64]), midwife (aOR 1.88 [95%CI 1.51-2.36]); previous IIV within 12 months of their current pregnancy (aOR 2.87 [95%CI 2.36-3.50]); and pertussis vaccination during the current pregnancy (aOR 4.88 [95%CI 4.08-5.83]). Conclusions and implications for public health: Healthcare provider discussions with pregnant women about the risks associated with influenza infection during pregnancy and early infancy and evidence about the safety and effectiveness of IIV are required. Recommending and offering IIV in pregnancy needs to be included in these discussions to improve uptake.

Absence of human papillomavirus in nasopharyngeal swabs from infants in a population at high risk of human papillomavirus infection.

Maternal urogenital human papillomavirus (HPV) infection may place neonates at risk of HPV acquisition and subsequently lower respiratory infections as HPV can influence development of immunity. The respiratory HPV prevalence is not known in remote-dwelling Aboriginal infants, who are at high risk of respiratory infection and where the population prevalence of urogenital HPV in women is high. These data are necessary to inform HPV vaccination regimens. A retrospective analysis using PCR specific for HPV was performed on 64 stored nasopharyngeal swabs from remote-dwelling Aboriginal infants < 6 months of age, with and without hospitalised pneumonia. HPV DNA was not detected in any specimen. Despite the negative result, we cannot exclude a role for HPV in respiratory infections affecting infants in this population; however, our data do not support HPV as an important contributor to acute respiratory infection in remote-dwelling Aboriginal children.

Can dried blood spots be used to accurately measure vitamin D metabolites?

BACKGROUND: Where conventional blood sampling is challenging, dried blood spots (DBS) provide a practical sample alternative for measuring vitamin D levels. Our study aimed to develop and evaluate a clinical pathology service-based assay suitable for measuring vitamin D in batches of DBS samples collected remote to the testing site. METHODS: A high throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with derivatisation was developed to measure 25-hydroxyvitamin D metabolites (25OHD3, 25OHD2 and 3-epi-25OHD3) in DBS samples. The assay was validated using paired DBS and plasma samples from 37 healthy adults. RESULTS: The assay reproducibly (<11.5% coefficient of variation) quantified 25OHD3 (range 1-300 nmol/L), 25OHD2 (range 2-300 nmol/L) and 3-epi-25OHD3 (range 1-200 nmol/L) in DBS samples. The 25OHD3 metabolite was detected in all DBS samples, 3-epi-25OHD3 in six plasma (range 2.1-6.3 nmol/L) and paired DBS samples, and 25OHD2 was not detected. Concentrations of 25OHD3 were highly correlated between paired samples: capillary DBS and venous plasma (r = 0.92), venous DBS and venous plasma (r = 0.93), and capillary DBS and venous DBS (r = 0.97). Ordinary least squares regression was used to characterise (ß = 0.81) and correct the systematic bias in DBS data (compared to paired plasma). Thereafter, Bland-Altman analysis demonstrated robust agreement between sample-methods. CONCLUSION: This simple and rapid DBS-based LC-MS/MS assay accurately quantified serum vitamin D metabolites using a paired-sample 'bridging strategy' to correct for the inherent sample-method bias.

Vitamin D Modulation of the Innate Immune Response to Paediatric Respiratory Pathogens Associated with Acute Lower Respiratory Infections.

Vitamin D is an essential component of immune function and childhood deficiency is associated with an increased risk of acute lower respiratory infections (ALRIs). Globally, the leading childhood respiratory pathogens are Streptococcus pneumoniae, respiratory syncytial virus and the influenza virus. There is a growing body of evidence describing the innate immunomodulatory properties of vitamin D during challenge with respiratory pathogens, but recent systematic and unbiased synthesis of data is lacking, and future research directions are unclear. We therefore conducted a systematic PubMed literature search using the terms "vitamin D" and "Streptococcus pneumoniae" or "Respiratory Syncytial Virus" or "Influenza". A priori inclusion criteria restricted the review to in vitro studies investigating the effect of vitamin D metabolites on human innate immune cells (primary, differentiated or immortalised) in response to stimulation with the specified respiratory pathogens. Eleven studies met our criteria. Despite some heterogeneity across pathogens and innate cell types, vitamin D modulated pathogen recognition receptor (PRRs: Toll-like receptor 2 (TLR2), TLR4, TLR7 and nucleotide-binding oligomerisation domain-containing protein 2 (NOD2)) expression; increased antimicrobial peptide expression (LL-37, human neutrophil peptide (HNP) 1-3 and ß-defensin); modulated autophagosome production reducing apoptosis; and modulated production of inflammatory cytokines (Interleukin (IL) -1ß, tumour necrosis factor-α (TNF-α), interferon-É£ (IFN-É£), IL-12p70, IFN-ß, Regulated on Activation, Normal T cell Expressed (RANTES), IL-10) and chemokines (IL-8 and C-X-C motif chemokine ligand 10 (CXCL10)). Differential modulation of PRRs and IL-1ß was reported across immune cell types; however, this may be due to the experimental design. None of the studies specifically focused on immune responses in cells derived from children. In summary, vitamin D promotes a balanced immune response, potentially enhancing pathogen sensing and clearance and restricting pathogen induced inflammatory dysregulation. This is likely to be important in controlling both ALRIs and the immunopathology associated with poorer outcomes and progression to chronic lung diseases. Many unknowns remain and further investigation is required to clarify the nuances in vitamin D mediated immune responses by pathogen and immune cell type and to determine whether these in vitro findings translate into enhanced immunity and reduced ALRI in the paediatric clinical setting.

Study Protocol for Preventing Early-Onset Pneumonia in Young Children Through Maternal Immunisation: A Multi-Centre Randomised Controlled Trial (PneuMatters).

Background: Preventing and/or reducing acute lower respiratory infections (ALRIs) in young children will lead to substantial short and long-term clinical benefits. While immunisation with pneumococcal conjugate vaccines (PCV) reduces paediatric ALRIs, its efficacy for reducing infant ALRIs following maternal immunisation has not been studied. Compared to other PCVs, the 10-valent pneumococcal-Haemophilus influenzae Protein D conjugate vaccine (PHiD-CV) is unique as it includes target antigens from two common lower airway pathogens, pneumococcal capsular polysaccharides and protein D, which is a conserved H. influenzae outer membrane lipoprotein. Aims: The primary aim of this randomised controlled trial (RCT) is to determine whether vaccinating pregnant women with PHiD-CV (compared to controls) reduces ALRIs in their infants' first year of life. Our secondary aims are to evaluate the impact of maternal PHiD-CV vaccination on different ALRI definitions and, in a subgroup, the infants' nasopharyngeal carriage of pneumococci and H. influenzae, and their immune responses to pneumococcal vaccine type serotypes and protein D. Methods: We are undertaking a parallel, multicentre, superiority RCT (1:1 allocation) at four sites across two countries (Australia, Malaysia). Healthy pregnant Australian First Nation or Malaysian women aged 17-40 years with singleton pregnancies between 27+6 and 34+6 weeks gestation are randomly assigned to receive either a single dose of PHiD-CV or usual care. Treatment allocation is concealed. Study outcome assessors are blinded to treatment arms. Our primary outcome is the rate of medically attended ALRIs by 12-months of age. Blood and nasopharyngeal swabs are collected from infants at birth, and at ages 6- and 12-months (in a subset). Our planned sample size (n = 292) provides 88% power (includes 10% anticipated loss to follow-up). Discussion: Results from this RCT potentially leads to prevention of early and recurrent ALRIs and thus preservation of lung health during the infant's vulnerable period when lung growth is maximum. The multicentre nature of our study increases the generalisability of its future findings and is complemented by assessing the microbiological and immunological outcomes in a subset of infants. Clinical Trial Registration: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374381, identifier: ACTRN12618000150246.

10-Valent pneumococcal non-typeable H. influenzae protein D conjugate vaccine (PHiD-CV10) versus 13-valent pneumococcal conjugate vaccine (PCV13) as a booster dose to broaden and strengthen protection from otitis media (PREVIX_BOOST) in Australian Aboriginal children: study protocol for a randomised controlled trial.

INTRODUCTION: Streptococcus pneumoniae and non-typeable Haemophilus influenzae (NTHi) are major otitis media pathogens that densely co-colonise the nasopharynx and infect the middle ear of Australian Aboriginal infants from very early in life. Our co-primary hypotheses are that at 18 months of age infants receiving 10-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine (PHiD-CV10) compared with those receiving 13-valent pneumococcal conjugate vaccine (PCV13) as a booster at 12 months of age will have higher antibody levels to Haemophilus influenzae protein D and that infants receiving PCV13 will have higher antibody levels to PCV13-only serotypes 3, 6A and 19A. METHODS AND ANALYSES: Our randomised controlled trial will enrol 270 Aboriginal children at 12 months of age to a booster dose of either PHiD-CV10 or PCV13. Children who completed the three-dose primary course schedules of PHiD-CV10 at 2, 4, 6 months of age; PCV13 at 2, 4, 6 months of age; or a combination schedule of PHiD-CV10 at 1, 2, 4 months of age plus PCV13 at 6 months of age are eligible. The co-primary assessor-blinded outcomes when the infants are 18 months of age are as follows: (a) IgG geometric mean concentration (GMC) and proportion with IgG ≥100 EU/mL for protein D, and (b) IgG GMC and the proportion with IgG ≥0.35 µg/mL for pneumococcal serotypes 3, 6A and 19A. Secondary immunogenicity comparisons of six primary and booster dose schedules of 10 shared serotypes at 18 months of age, nasopharyngeal carriage, all forms of otitis media, hearing loss and developmental milestones at 18, 24, 30 and 36 months of age will be reported. ETHICS AND DISSEMINATION: Ethics committees of NT Department of Health, Menzies, WA Department of Health and WA Aboriginal Health approved the study. Results will be presented to communities, at conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT01735084.

Acute lower respiratory infections in Indigenous infants in Australia's Northern Territory across three eras of pneumococcal conjugate vaccine use (2006-15): a population-based cohort study.

BACKGROUND: The burden of acute lower respiratory infection (ALRI) in Indigenous children of Australia's Northern Territory is among the highest globally. No published data exists on the effect of pneumococcal conjugate vaccine (PCV) introduction on ALRIs in this population beyond 2005. The aim of this study was to describe the rates of ALRI admissions to hospital in Indigenous infants in the Northern Territory from 2006 to 2015, across three periods of different PCV use. We hypothesised that broader valency PCVs would be more effective against hospitalisations for pneumonia. METHODS: We did a retrospective population-based cohort study of Indigenous infants born in the Northern Territory followed up until age 12 months. Data were from administrative hospital and perinatal datasets. International classification of diseases codes (tenth revision, Australian modification; ICD-10AM) were used to identify respiratory hospitalisations of interest: all-cause ALRI, all-cause pneumonia, bacterial pneumonia, viral pneumonia, influenza-like illness (ILI), respiratory syncytial virus ALRI (RSV-ALRI), and pneumococcal ALRI. Incidence rates were compared between PCV eras (7-valent PCV [PCV7], 2006-09; 10-valent PCV [PCV10], 2009-11; and 13-valent PCV [PCV13], 2011-15) using interrupted time trend analysis and negative binomial regression. FINDINGS: For children born between Jan 1, 2006, and Dec 31, 2015, 4138 ALRI episodes (31% of all hospitalisations) occurred among 2888 (20%) of the 14 594 infants. The overall ALRI hospitalisation rate was 29·7 episodes per 100 child-years. Prominent risk factors associated with ALRI hospitalisation were living in a remote community or the Central desert region, being born preterm or with low birthweight. ALRI rates were lowest in the PCV13 era, in association with a significant reduction in bacterial pneumonia hospitalisations in the PCV13 era compared with the PCV10 (incidence rate ratio 0·68, 95% CI 0·57-0·81) and PCV7 (0·70, 0·60-0·81) eras. In contrast, RSV-ALRI rates were 4·9 episodes per 100 child-years in each era. INTERPRETATION: A 30% reduction in bacterial-coded pneumonia hospitalisations in the Northern Territory during the era of PCV13 immunisation supports its ongoing use in the region. Despite the reduction, one in five Indigenous infants born in the region continue to be hospitalised with an ALRI in their first year of life. Future gains require multifaceted environmental and biomedical approaches. FUNDING: National Health and Medical Research Council of Australia.

Influenza vaccination in pregnancy among a group of remote dwelling Aboriginal and Torres Strait Islander mothers in the Northern Territory: The 1+1 Healthy Start to Life study.

Remote-living Aboriginal and Torres Strait Islander women experience a higher burden of influenza infection during pregnancy than any other Australian women. Despite recommendations of inactivated influenza vaccination (IIV) in pregnancy, uptake and safety data are scarce for this population. We examined uptake of IIV in pregnancy and report adverse birth outcomes amongst a predominantly unvaccinated group of remote-living Aboriginal and Torres Strait Islander women from the Northern Territory (NT), using data from the 1+1 Healthy Start to Life study. Data were deterministically linked with the NT Immunisation Register to ascertain IIV exposure in pregnant women during 2003-2006 and 2009-2011 inclusive. Overall, IIV uptake in pregnancy was 3% (n=20/697 pregnancies); 0% (0/414) pre-influenza A(H1N1)pdm09 and 7% (20/293) post-influenza A(H1N1)pdm09 (2009-2011). Vaccine uptake was poor in this cohort and it is unclear at what stage this policy failure occurred. Women with known comorbidities and/or high risk factors were not targeted for vaccination. Much larger study participant numbers are required to validate between group comparisons but there was no clinically nor statistically significant difference in median gestational ages (38 weeks for both groups), mean infant birthweights (3,001 g unvaccinated vs 3,175 g IIV vaccinated), nor birth outcomes between the few women who received IIV in pregnancy and those who did not. There were no stillbirths in women who received an IIV in pregnancy.