COVID-19 Vaccine Uptake by Infection Status in New South Wales, Australia.

Using linked public health data from Australia to measure uptake of COVID-19 vaccination by infection status, we found coverage considerably lower among infected than uninfected persons for all ages. Increasing uptake of scheduled doses, including among previously infected persons after the recommended postinfection delay, is needed to reduce COVID-19 illness rates.

Levels of pneumococcal conjugate vaccine coverage and indirect protection against invasive pneumococcal disease and pneumonia hospitalisations in Australia: An observational study.

BACKGROUND: There is limited empiric evidence on the coverage of pneumococcal conjugate vaccines (PCVs) required to generate substantial indirect protection. We investigate the association between population PCV coverage and indirect protection against invasive pneumococcal disease (IPD) and pneumonia hospitalisations among undervaccinated Australian children. METHODS AND FINDINGS: Birth and vaccination records, IPD notifications, and hospitalisations were individually linked for children aged <5 years, born between 2001 and 2012 in 2 Australian states (New South Wales and Western Australia; 1.37 million children). Using Poisson regression models, we examined the association between PCV coverage, in small geographical units, and the incidence of (1) 7-valent PCV (PCV7)-type IPD; (2) all-cause pneumonia; and (3) pneumococcal and lobar pneumonia hospitalisation in undervaccinated children. Undervaccinated children received <2 doses of PCV at <12 months of age and no doses at ≥12 months of age. Potential confounding variables were selected for adjustment a priori with the assistance of a directed acyclic graph. There were strong inverse associations between PCV coverage and the incidence of PCV7-type IPD (adjusted incidence rate ratio [aIRR] 0.967, 95% confidence interval [CI] 0.958 to 0.975, p-value < 0.001), and pneumonia hospitalisations (all-cause pneumonia: aIRR 0.991 95% CI 0.990 to 0.994, p-value < 0.001) among undervaccinated children. Subgroup analyses for children <4 months old, urban, rural, and Indigenous populations showed similar trends, although effects were smaller for rural and Indigenous populations. Approximately 50% coverage of PCV7 among children <5 years of age was estimated to prevent up to 72.5% (95% CI 51.6 to 84.4) of PCV7-type IPD among undervaccinated children, while 90% coverage was estimated to prevent 95.2% (95% CI 89.4 to 97.8). The main limitations of this study include the potential for differential loss to follow-up, geographical misclassification of children (based on residential address at birth only), and unmeasured confounders. CONCLUSIONS: In this study, we observed substantial indirect protection at lower levels of PCV coverage than previously described-challenging assumptions that high levels of PCV coverage (i.e., greater than 90%) are required. Understanding the association between PCV coverage and indirect protection is a priority since the control of vaccine-type pneumococcal disease is a prerequisite for reducing the number of PCV doses (from 3 to 2). Reduced dose schedules have the potential to substantially reduce program costs while maintaining vaccine impact.

Seroprevalence of SARS-CoV-2-specific antibodies in Sydney after the first epidemic wave of 2020.

OBJECTIVES: To estimate SARS-CoV-2-specific antibody seroprevalence after the first epidemic wave of coronavirus disease 2019 (COVID-19) in Sydney. SETTING, PARTICIPANTS: People of any age who had provided blood for testing at selected diagnostic pathology services (general pathology); pregnant women aged 20-39 years who had received routine antenatal screening; and Australian Red Cross Lifeblood plasmapheresis donors aged 20-69 years. DESIGN: Cross-sectional study; testing of de-identified residual blood specimens collected during 20 April - 2 June 2020. MAIN OUTCOME MEASURE: Estimated proportions of people seropositive for anti-SARS-CoV-2-specific IgG, adjusted for test sensitivity and specificity. RESULTS: Thirty-eight of 5339 specimens were IgG-positive (general pathology, 19 of 3231; antenatal screening, 7 of 560; plasmapheresis donors, 12 of 1548); there were no clear patterns by age group, sex, or location of residence. Adjusted estimated seroprevalence among people who had had general pathology blood tests (all ages) was 0.15% (95% credible interval [CrI], 0.04-0.41%), and 0.29% (95% CrI, 0.04-0.75%) for plasmapheresis donors (20-69 years). Among 20-39-year-old people, the age group common to all three collection groups, adjusted estimated seroprevalence was 0.24% (95% CrI, 0.04-0.80%) for the general pathology group, 0.79% (95% CrI, 0.04-1.88%) for the antenatal screening group, and 0.69% (95% CrI, 0.04-1.59%) for plasmapheresis donors. CONCLUSIONS: Estimated SARS-CoV-2 seroprevalence was below 1%, indicating that community transmission was low during the first COVID-19 epidemic wave in Sydney. These findings suggest that early control of the spread of COVID-19 was successful, but efforts to reduce further transmission remain important.

Childhood vaccination coverage in Australia: an equity perspective.

BACKGROUND: This study describes trends in social inequities in first dose measles-mumps-rubella (MMR1) vaccination coverage in Western Australia (WA) and New South Wales (NSW). Using probabilistically-linked administrative data for 1.2 million children born between 2002 and 2011, we compared levels and trends in MMR1 vaccination coverage measured at age 24 months by maternal country of birth, Aboriginal status, maternal age at delivery, socio-economic status, and remoteness in two states. RESULTS: Vaccination coverage was 3-4% points lower among children of mothers who gave birth before the age of 20 years, mothers born overseas, mothers with an Aboriginal background, and parents with a low socio-economic status compared to children that did not belong to these social groups. In both states, between 2007 and 2011 there was a decline of 2.1% points in MMR1 vaccination coverage for children whose mothers were born overseas. In 2011, WA had lower coverage among the Aboriginal population (89.5%) and children of young mothers (89.3%) compared to NSW (92.2 and 92.1% respectively). CONCLUSION: Despite overall high coverage of MMR1 vaccination, coverage inequalities increased especially for children of mothers born overseas. Strategic immunisation plans and policy interventions are important for equitable vaccination levels. Future policy should target children of mothers born overseas and Aboriginal children.

Women's empowerment is associated with maternal nutrition and low birth weight: evidence from Bangladesh Demographic Health Survey.

BACKGROUND: The burden of maternal undernutrition and low birth weight (LBW) incurs enormous economic costs due to their adverse consequences. Women's empowerment is believed to be one of the key factors for attaining maternal and child health and nutritional goals. Our objective was to investigate the association of women's empowerment with maternal undernutrition and LBW. METHODS: We used nationally representative data from the Bangladesh Demographic Health Survey for 2011 and 2014. We analysed 27357 women and 9234 mother-child pairs. A women's empowerment index (WEI) was constructed using principal component analysis with five groups of indicators: a) education, b) access to socio-familial decision making, c) economic contribution and access to economic decision making, d) attitudes towards domestic violence and e) mobility. We estimated odds ratios as the measure of association between the WEI and the outcome measures using generalized estimating equations to account for the cluster level correlation. RESULTS: The overall prevalence of maternal undernutrition was 20% and LBW was 18%. The WEI was significantly associated with both maternal undernutrition and LBW with a dose-response relationship. The adjusted odds of having a LBW baby was 32% [AOR (95% CI): 0.68 (0.57, 0.82)] lower in the highest quartile of the WEI relative to the lowest quartile. Household wealth significantly modified the effect of the WEI on maternal nutrition; in the highest wealth quintile, the odds of maternal undernutrition was 54% [AOR (95% CI): 0.46 (0.33, 0.64)] lower while in the lowest wealth quintile the odds of undernutrition was only 18% [AOR (95% CI): 0.82 (0.67, 1.00)] lower comparing the highest WEI quartile with the lowest WEI quartile. However, the absolute differences in prevalence of undernutrition between the highest and lowest WEI quartiles were similar across wealth quintiles (6-8%). CONCLUSIONS: This study used a comprehensive measure of women's empowerment and provides strong evidence that low levels of women's empowerment are associated with maternal undernutrition as well as with delivering LBW babies in Bangladesh. Therefore, policies to increase empowerment of women would contribute to improved public health.

Seroprevalence of Q fever among metropolitan and non-metropolitan blood donors in New South Wales and Queensland, 2014-2015.

OBJECTIVES: To estimate the prevalence of exposure to the causative agent of Q fever (Coxiella burnetii) and of current infections among blood donors in Australia. DESIGN, SETTING: Cross-sectional study in metropolitan Sydney and Brisbane, and in non-metropolitan regions with high Q fever notification rates (Hunter New England in New South Wales; Toowoomba in Queensland). PARTICIPANTS: Blood donors attending Red Cross collection centres during October 2014 - June 2015 who provided sera and completed a questionnaire on Q fever vaccination status, diagnosis and knowledge, and exposure history. MAIN OUTCOME MEASURES: Age- and sex-standardised seroprevalence of phase II IgG antibodies to C. burnetii (indicating past exposure) and independent risk factors for seropositivity; presence of C. burnetii DNA (indicating current infection and risk of transmission by blood transfusion). RESULTS: 2740 donors (94.5% response rate) completed the questionnaire and supplied sera for analysis. Crude antibody seroprevalence was 3.6%. Standardised seroprevalence was higher in non-metropolitan than metropolitan regions (NSW, 3.7% v 2.8%; Queensland, 4.9% v 1.6%; statistically significant only in Queensland). Independent predictors of antibody seropositivity were regular contact with sheep, cattle, or goats (adjusted odds ratio [aOR], 5.3; 95% CI, 2.1-14), abattoir work (aOR, 2.2; 95% CI, 1.2-3.9), and assisting at an animal birth (aOR, 2.1; 95% CI, 1.2-3.6). Having lived in a rural area but having only rare or no contact with sheep, cattle or goats was itself a significant risk factor (v never lived rurally: aOR, 2.5; 95% CI, 1.1-5.9). 40% of people in groups recommended for vaccination were aware of the vaccine; 10% of people in these groups had been vaccinated. C. burnetii DNA was not detected in 1681 non-metropolitan samples, suggesting that transmission by blood donation is unlikely. CONCLUSIONS: Given their exposure to multiple risk factors, vaccination against Q fever should be considered for all rural residents.

Patterns of Drug Use and Drug-related Hospital Admissions in HIV-Positive and -Negative Gay and Bisexual Men.

We aimed to compare rates of illicit drug-related hospitalisations in HIV-negative (HIV-ve) (n = 1325) and HIV-positive (HIV+ve) (n = 557) gay and bisexual men (GBM) with rates seen in the general male population and to examine the association between self-reported illicit drug use and drug-related hospitalisation. Participants were asked how often they used a range of illicit drugs in the previous 6 months at annual interviews. Drug-related hospital admissions were defined as hospital admissions for mental or behavioural disorders due to illicit drug use (ICD 10: F11-16, F18, F19), drug poisoning (T40-T45, T50) or toxic effect of gases (T53, T59, T65). Drug-related hospitalisations were 4.8 times higher in the HIV-ve cohort [SIR 4.75 (95 % CI 3.30-6.91)] and 3.5 times higher in the HIV+ve cohort [SIR 3.51 (1.92-5.88)] compared with the general population. Periods of weekly drug use [IRR 1.86 (1.01-3.46)], poly-drug use [IRR 2.17 (1.07-4.38)] and cannabis use [low use-IRR 1.95 (1.01-3.77), high use-IRR 2.58 (1.29-5.16)] were associated with drug-related hospitalisation in both cohorts, as was being a consistently high meth/amphetamine user throughout follow-up [IRR 3.24 (1.07-9.83)] and being an inconsistent or consistent injecting drug user throughout follow-up [IRR 3.94 (1.61-9.66), IRR 4.43(1.04-18.76), respectively]. Other risk factors for drug-related hospitalisation indicated the likelihood of comorbid drug and mental health issues in GBM hospitalised for drug use.

Risk factors and burden of acute Q fever in older adults in New South Wales: a prospective cohort study.

OBJECTIVES: To measure the acute burden of and to identify risk factors associated with notified Q fever in older adults in New South Wales. DESIGN, SETTINGS AND PARTICIPANTS: A prospective cohort of adults aged 45 years and over (the 45 and Up Study) recruited during 2006-2009 and followed using linked Q fever notifications, hospital records and death records during 2006-2012. MAIN OUTCOME MEASURES: Incident cases of Q fever, based on a linked Q fever notification; proportion of cases with a Q fever-coded hospitalisation. RESULTS: A total of 266 906 participants were followed up for 1 254 650 person-years (mean, 4.7 ± 1.0 years per person). In our study population, the incidence of notified Q fever during follow-up was 3.6 (95% CI, 2.7-4.8) per 100 000 person-years. After adjustments, age (≥ 65 years v 45-54 years: hazard ratio [HR], 0.39; 95% CI, 0.16-0.96), sex (women v men: HR, 0.48; 95% CI, 0.26-0.88), and area and type of residence (P < 0.001 for trend) remained significantly associated with Q fever. Compared with those living in an inner regional area but not on a farm, the risk of notified Q fever was highest for those living on a farm in outer regional or remote areas (HR, 11.98; 95% CI, 5.47-26.21), followed by those living on a farm in inner regional areas (HR, 4.95; 95% CI, 1.79-13.65). Of notified Q fever cases, 15 of 39 (38%) had been hospitalised with a diagnosis consistent with Q fever. CONCLUSIONS: Adults living on a farm in outer regional and remote areas are at a substantially greater risk of contracting Q fever. This suggests that, as well as targeting specific occupational groups for vaccination, there would be benefits in increasing public awareness of Q fever and vaccination among those living on and near farms in outer regional and remote areas of Australia.

Estimating the measles effective reproduction number in Australia from routine notification data.

OBJECTIVE: To estimate the measles effective reproduction number (R) in Australia by modelling routinely collected notification data. METHODS: R was estimated for 2009-2011 by means of three methods, using data from Australia's National Notifiable Disease Surveillance System. Method 1 estimated R as 1 - P, where P equals the proportion of cases that were imported, as determined from data on place of acquisition. The other methods estimated R by fitting a subcritical branching process that modelled the spread of an infection with a given R to the observed distributions of outbreak sizes (method 2) and generations of spread (method 3). Stata version 12 was used for method 2 and Matlab version R2012 was used for method 3. For all methods, calculation of 95% confidence intervals (CIs) was performed using a normal approximation based on estimated standard errors. FINDINGS: During 2009-2011, 367 notifiable measles cases occurred in Australia (mean annual rate: 5.5 cases per million population). Data were 100% complete for importation status but 77% complete for outbreak reference number. R was estimated as < 1 for all years and data types, with values of 0.65 (95% CI: 0.60-0.70) obtained by method 1, 0.64 (95% CI: 0.56-0.72) by method 2 and 0.47 (95% CI: 0.38-0.57) by method 3. CONCLUSION: The fact that consistent estimates of R were obtained from all three methods enhances confidence in the validity of these methods for determining R.

Rapid identification of group B streptococcus carriage by PCR to assist in the management of women with prelabour rupture of membranes in term pregnancy.

BACKGROUND: Management of prelabour rupture of membranes at term (37 weeks gestation or later) (TPROM) remains complicated in the absence of a rapid assay for group B streptococcus (GBS) colonisation. AIMS: To evaluate the accuracy and clinical utility of a commercial PCR assay, compared with culture, for detection of GBS colonisation in pregnant women presenting with TPROM. METHODS: A prospective study of women presenting with TPROM conducted in a large tertiary hospital (Westmead Hospital, Australia). Five hundred and seventy-four consecutive women with TPROM were enrolled between July 2006 and November 2007. Paired low vaginal and anal swabs were collected from women presenting with TPROM for PCR and culture on GBS selective agar following broth enrichment. Primary outcomes were sensitivity and specificity of PCR compared with GBS selective enrichment culture. Secondary analyses included comparison with a historical but otherwise similar cohort regarding clinical utility, maternal and neonatal outcomes. RESULTS: PCR sensitivity and specificity were 89.0% (95% CI - 82.8-93.6%) and 97.9% (95% CI - 96.0-99.0%), respectively, compared with culture. 72.3% of women were aware of their GBS PCR status within 3 h of presentation. Compared with the historical cohort, PCR reduced the requirement for intrapartum antibiotics by 25.6% (P < 0.001). There were no significant differences in maternal outcomes or combined rates of admissions to neonatal intensive care or special care nursery. CONCLUSIONS: Group B streptococcus PCR is an accurate, rapid, safe and practical alternative to culture for detection of GBS colonisation in pregnant women at the time of TPROM. This method has the potential advantage to reduce costs associated with length of hospital stay.

Infant Whole-Cell Versus Acellular Pertussis Vaccination in 1997 to 1999 and Risk of Childhood Hospitalization for Food-Induced Anaphylaxis: Linked Administrative Databases Cohort Study.

BACKGROUND: Evidence suggests that children who had received an initial priming dose of whole-cell pertussis (wP) vaccine, rather than acellular pertussis (aP) vaccine, had a lower risk of developing IgE-mediated food allergy, the most common cause of anaphylaxis-related hospital presentations of childhood. OBJECTIVE: To assess the association between wP versus aP vaccination in infancy and subsequent hospital presentations for anaphylaxis. METHODS: This study was preregistered under PMID 34874968. Perinatal records for a cohort of New South Wales-born children (1997-1999) receiving their first dose of pertussis-containing vaccine before age 4 months were probabilistically linked to hospital and immunization records. We used adjusted Cox models to estimate hazard ratios (aHRs) and 95% CIs for anaphylaxis-coded hospitalizations. RESULTS: There were 218,093 New South Wales-born children who received a first dose of wP or aP before age 4 months. Among these children, 86 experienced at least one hospitalization for food-induced anaphylaxis at age 5-15 years (range of events per patient, one to three). The person-time of follow-up was 1,476,969 years, and 665,519 years for children vaccinated with wP as a first dose (wP-1 children) and aP as a first dose (aP-1 children), respectively. The incidence rates for first hospitalization for food anaphylaxis were 3.5 (95% CI, 2.6-4.6) and 5.1 (95% CI, 3.5-7.1) per 100,000 child-years among wP-1 children and aP-1 children, respectively (aHR for wP vs aP = 0.47; 95% CI, 0.26-0.83). For first admission for venom anaphylaxis, the incidence rate was 4.9 (95% CI, 3.9-6.2) per 100,000 child-years among wP-1 children and 5.1 (95% CI, 3.5-7.1) per 100,000 child-years among aP-1 children (aHR for wP vs aP = 0.92; 95% CI, 0.53-1.60), and for all-cause anaphylaxis, the incidence rate was 10.6 (95% CI, 9.0-12.4) per 100,000 child-years among wP-1 children and 12.8 (95% CI, 10.2-15.8) per 100,000 child-years among aP-1 children (aHR for wP vs aP = 0.92; 95% CI, 0.53-1.60). CONCLUSION: Vaccination with wP in infancy was associated with a lower risk of hospitalizations for food-induced anaphylaxis (and therefore severe IgE-mediated food allergy) occurring in childhood.

Measles, mumps, rubella and varicella antibodies among international and domestic university students.

BACKGROUND: Vaccine-preventable infections are generally well controlled in Australia. However, gaps in immunity can lead to outbreaks and are important to identify. Young adults are a highly mobile population and a potential source of imported infections. We aimed to evaluate anti- measles, mumps, rubella and varicella (MMR&V) IgG seroprevalence and explore factors relating to antibody seropositivity. METHODS: A cross-sectional online survey was conducted among students from a large Australian university to collect demographic, vaccination, infection and travel characteristics. Blood samples were collected to measure MMR&V seroprevalence. Logistic regression was used to identify factors associated with seropositivity. RESULTS: Among 804 university students, seroprevalence (positive or equivocal) for measles was 82.3% (95% CI 79.6-84.8%), mumps 79.5% (95% CI 76.7-82.3%), rubella 91.5% (95% CI 89.6-93.5%) and varicella 86.2% (95% CI 84.1-88.8%), with 452 (56.2%, 95% CI 52.8-59.6) seropositive to all four viruses. Varicella seropositivity was highest in the older birth cohort (born 1988-1991). Measles seropositivity was higher for international students compared to domestic students. Among international students, mumps seroprevalence was significantly lower than measles and rubella seroprevalence. International travel in the previous 12 months was reported by 63.1% of students, but only 18.2% of travellers reported seeking pre-travel health advice prior to most recent international travel. CONCLUSIONS: Overall, this study suggests immunity to MMR&V is sub-optimal. We found the university student population to be highly mobile and unlikely to seek pre-travel advice; thus, they are a potential source of infection importation. The implementation of university immunization policies could address the gaps identified and our findings can inform the development of targeted vaccination campaigns.

Acute Q fever in patients with an influenza-like illness in regional New South Wales, Australia.

INTRODUCTION: Query (Q) fever is a zoonosis caused by the bacterium Coxiella burnetii typically presenting as an influenza-like illness (ILI) with or without hepatitis. The infection may be missed by clinicians in settings of low endemicity, as the presentation is clinically not specific, and there are many more common differential diagnoses for ILI including SARS-CoV-2 infection. METHODS: Residual serum samples were retrospectively tested for Phase 1 and 2 Q fever-specific IgM, IgG, IgA antibodies by indirect immunofluorescence and C. burnetii DNA by polymerase chain reaction. They had not been previously tested for Q fever, originating from undiagnosed patients with probable ILI, aged 10-70 years and living in regional New South Wales, Australia. The results were compared with contemperaneous data on acute Q fever diagnostic tests which had been performed based on clinicians requests from a geographically similar population. RESULTS: Only one (0.2%) instance of missed acute Q fever was identified after testing samples from 542 eligible patients who had probable ILI between 2016-2023. Laboratory data showed that during the same period, 731 samples were tested for acute Q fever for clinician-initiated requests and of those 70 (9.6%) were positive. Probability of being diagnosed with Q fever after a clinician initiated request was similar regardless of the patients sex, age and the calendar year of sampling. CONCLUSION: In this sample, Q fever was most likely to be diagnosed via clinician requested testing rather than by testing of undiagnosed patients with an influenza like illness.

Country of birth and other factors associated with hepatitis B prevalence in a population with high levels of immigration.

BACKGROUND AND AIM: While hepatitis B virus (HBV) prevalence is known to vary greatly between countries, systematically collected population-level prevalence data from some countries is limited. Antenatal HBV screening programs in countries with substantial migrant populations provide the opportunity to systematically examine HBV prevalence in order to inform local and regional HBV estimates. METHODS: A comprehensive register of Australian mothers giving birth from January 2000 to December 2008 was linked to a register of HBV notifications. Age-standardized prevalence of chronic HBV were calculated overall and by the mother's country of birth. Multiple logistic regression was used to investigate other factors associated with HBV prevalence. RESULTS: Five hundred twenty-three thousand six hundred sixty-five women were included and linked to 3861 HBV notifications. The age-standardized HBV prevalence was low (0.75%, 95% confidence interval 0.72-0.79). The highest HBV prevalence rates were observed in women born in Cambodia (8.60%), Taiwan (8.10%), Vietnam (7.49%), China (6.80%), and Tonga (6.51%). Among Australia-born women, those who smoked during pregnancy, were from a more disadvantaged socioeconomic background, and lived in remote areas were more likely to have HBV. There was also a trend suggesting a decrease in the prevalence of HBV over time. CONCLUSIONS: Antenatal screening for HBV can provide systematic population estimates of HBV prevalence in migrants and also identify other high prevalence groups. Longer follow-up will be required to confirm the small decrease in HBV prevalence observed in this study.

Association between pertussis vaccination in infancy and childhood asthma: A population-based record linkage cohort study.

BACKGROUND: Asthma is among the commonest noncommunicable diseases of childhood and often occurs with other atopic comorbidities. A previous case-control study found evidence that compared to children who received acellular pertussis (aP) vaccines in early infancy, children who received one or more doses of whole-cell pertussis (wP) vaccine had lower risk of developing IgE-mediated food allergy. We hypothesized that wP vaccination in early infancy might protect against atopic asthma in childhood. METHODS: Retrospective record-linkage cohort study of children between 5 and < 15 years old and born between January 1997, and December 1999, in the Australian states of Western Australia (WA) and New South Wales (NSW), receiving wP versus aP vaccine as the first pertussis vaccine dose. The main outcome and measures were first and recurrent hospitalizations for asthma; hazard ratios (HRs) and 95% confidence intervals (CIs) were computed by means of Cox and Andersen and Gill models. RESULTS: 274,405 children aged between 5 and < 15 years old (78.4% NSW-born) received a first dose of either wP (67.8%) or aP vaccine before 4 months old. During the follow-up period, there were 5,905 hospitalizations for asthma among 3,955 children. The incidence rate for first hospitalization was 1.5 (95% CI 1.4-1.5) per 1,000 child-years among children receiving wP vaccine as a first dose, and 1.5 (95% CI 1.4-1.6) among those vaccinated with aP vaccine as a first dose. The adjusted HRs for those who received wP vaccine versus aP vaccine as the first dose were 1.02 (95% CI 0.94-1.12) for first hospitalizations and 1.07 (95% CI 0.95-1.2) for recurrent hospitalizations for asthma. CONCLUSIONS: We found no convincing evidence of a clinically relevant association between receipt of wP versus aP vaccines in early infancy and hospital presentations for asthma in childhood.

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

BACKGROUND: The impact of pneumococcal conjugate vaccines (PCVs) on pneumonia in children is well-documented but data on 23-valent pneumococcal polysaccharide vaccine (PPV23) are lacking. Between 2001 and 2011, Indigenous children in Western Australia (WA) were recommended to receive PPV23 at 18-24 months of age following 3 doses of 7-valent PCV. We evaluated the incremental effectiveness of PPV23 against pneumonia hospitalisation. METHODS: Indigenous children born in WA between 2001 and 2012 who received PCV dose 3 by 12 months of age were followed from 18 to 60 months of age for the first episode of pneumonia hospitalisation (all-cause and 3 subgroups: presumptive pneumococcal, other specified causes, and unspecified). We used Cox regression modelling to estimate hazard ratios (HRs) for pneumonia hospitalisation among children who had, versus had not, received PPV23 between 18 and 30 months of age after adjustment for confounders. RESULTS: 11,120 children had 327 first episodes of all-cause pneumonia hospitalisation, with 15 (4.6%) coded as presumptive pneumococcal, 46 (14.1%) as other specified causes and 266 (81.3%) unspecified. No statistically significant reduction in all-cause pneumonia was seen with PPV23 (HR 1.11; 95% CI: 0.87-1.43), but the direction of the association differed for presumptive pneumococcal (HR 0.47; 95% CI: 0.16-1.35) and specified (HR 0.89; 95% CI: 0.49-1.62) from unspecified causes (HR 1.13; 95% CI: 0.86-1.49). During the baseline period before PPV23 vaccination (12-18 months), all-cause pneumonia risk was higher among PPV23-vaccinated than unvaccinated children (RR: 1.73; 95% CI: 1.30-2.28). CONCLUSION: In this high-risk population, no statistically significant incremental effect of a PPV23 booster at 18-30 months was observed against hospitalised all-cause pneumonia or the more specific outcome of presumptive pneumococcal pneumonia. Confounding by indication may explain the slight trend towards an increased risk against all-cause pneumonia. Larger studies with better control of confounding are needed to further inform PPV23 vaccination.

Estimating the excess burden of pertussis disease in Australia within the first year of life, that might have been prevented through timely vaccination.

BACKGROUND: Previous Australian studies have shown that delayed vaccination with each of the three primary doses of diphtheria-tetanus-pertussis-containing vaccines (DTP) is up to 50 % in certain subpopulations. We estimated the excess burden of pertussis that might have been prevented if (i) all primary doses and (ii) each dose was given on time. METHODS: Perinatal, immunization, pertussis notification and death data were probabilistically linked for 1 412 984 infants born in two Australian states in 2000-12. A DTP dose administered >15 days after the recommended age was considered delayed. We used Poisson regression models to compare pertussis notification rates to 1-year of age in infants with ≥1 dose delayed (Aim 1) or any individual dose delayed (Aim 2) versus a propensity weighted counterfactual on-time cohort. RESULTS: Of all infants, 42% had ≥1 delayed DTP dose. We estimated that between 39 to 365 days of age, 85 (95% CI: 61-109) cases per 100 000 infants, could have been prevented if all infants with ≥1 delayed dose had received their three doses within the on-time window. Risk of pertussis was higher in the delayed versus the on-time cohort, so crude rates overestimated the excess burden (110 cases per 100 000 infants (95% CI: 95-125)). The estimated dose-specific excess burden per 100 000 infants was 132 for DTP1, 50 for DTP2 and 19 for DTP3. CONCLUSIONS: We provide robust evidence that improved DTP vaccine timeliness, especially for the first dose, substantially reduces the burden of infant pertussis. Our methodology, using a potential outcomes framework, is applicable to other settings.

Hepatitis C treatment outcomes in Australian clinics.

OBJECTIVE: To determine hepatitis C (HCV) treatment effectiveness and predictors of response in the "real-world" Australian clinic setting. DESIGN, SETTING AND PARTICIPANTS: Patients with chronic HCV, who were HCV-treatment-naive at enrolment, and were then treated with standard therapy (pegylated interferon-α plus ribavirin), were recruited prospectively through a national network of 24 HCV clinics between April 2008 and December 2009. Patients were interviewed and a medical record review was conducted at enrolment and at routine follow-up clinic visits. MAIN OUTCOME MEASURES: Proportion of patients achieving a sustained virological response (SVR), predictors of SVR, and impact of treatment on biochemical markers of liver disease (alanine aminotransferase levels and aspartate aminotransferase-to-platelet ratio index scores). RESULTS: The SVR by intention to treat was 60% (327/550). Infection with HCV genotype 2 or 3 (compared with genotype 1) was an independent predictor of SVR (odds ratio [OR], 2.45; 95% CI, 1.70-3.52), while HIV coinfection (OR, 0.28; 95% CI, 0.10-0.82), cirrhosis (OR, 0.38; 95% CI, 0.18-0.81), and increased body mass index for ≥ 30 kg/m(2) v ≤ 25 kg/m(2) (OR, 0.58; 95% CI, 0.35-0.96) were independently associated with lower SVR. There was a significant improvement in biochemical markers of liver disease following SVR (P< 0.001). CONCLUSIONS: Our findings are similar to those seen in clinical trials, despite the inclusion of patients with a broad range of comorbid conditions such as injecting drug and alcohol use and psychiatric illness. They suggest that, with appropriate patient and infrastructure support, expansion of treatment services to the broader HCV-infected community is warranted.

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

BACKGROUND: Children with chronic medical conditions are at higher risk of invasive pneumococcal disease (IPD), but little is known about the effectiveness of the primary course of pneumococcal conjugate vaccine (PCV) in these children. METHODS: A cohort born in 2001-2004 from two Australian states and identified as medically at-risk (MAR) of IPD either using ICD-coded hospitalizations (with conditions of interest identified by 6 months of age) or linked perinatal data (for prematurity) were followed to age 5 years for notified IPD by serotype. We categorized fully vaccinated children as either receiving PCV dose 3 by <12 months of age or ≥1 PCV dose at ≥12 months of age. Cox proportional hazard modeling was used to estimate hazard ratios (HRs), adjusted for confounders, and vaccine effectiveness (VE) was estimated as (1-HR) × 100. RESULTS: A total of 9220 children with MAR conditions had 53 episodes of IPD (43 vaccine-type); 4457 (48.3%) were unvaccinated and 4246 (46.1%) were fully vaccinated, with 1371 (32.3%) receiving dose 3 by 12 months and 2875 (67.7%) having ≥1 dose at ≥12 months. Estimated VE in fully vaccinated children was 85.9% (95% CI: 33.9-97.0) against vaccine-type IPD and 71.5% (95% CI: 26.6-88.9) against all-cause IPD. CONCLUSION: This is the first population-based study evaluating the effectiveness of PCV in children with MAR conditions using record linkage. Our study provides evidence that the VE for vaccine-type and all-cause IPD in MAR children in Australia is high and not statistically different from previously reported estimates for the general population. This method can be replicated in other countries to evaluate VE in MAR children.