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.

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.

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.

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.

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.

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.

Serological testing of blood donors to characterise the impact of COVID-19 in Melbourne, Australia, 2020.

Rapidly identifying and isolating people with acute SARS-CoV-2 infection has been a core strategy to contain COVID-19 in Australia, but a proportion of infections go undetected. We estimated SARS-CoV-2 specific antibody prevalence (seroprevalence) among blood donors in metropolitan Melbourne following a COVID-19 outbreak in the city between June and September 2020. The aim was to determine the extent of infection spread and whether seroprevalence varied demographically in proportion to reported cases of infection. The design involved stratified sampling of residual specimens from blood donors (aged 20-69 years) in three postcode groups defined by low (<3 cases/1,000 population), medium (3-7 cases/1,000 population) and high (>7 cases/1,000 population) COVID-19 incidence based on case notification data. All specimens were tested using the Wantai SARS-CoV-2 total antibody assay. Seroprevalence was estimated with adjustment for test sensitivity and specificity for the Melbourne metropolitan blood donor and residential populations, using multilevel regression and poststratification. Overall, 4,799 specimens were collected between 23 November and 17 December 2020. Seroprevalence for blood donors was 0.87% (90% credible interval: 0.25-1.49%). The highest estimates, of 1.13% (0.25-2.15%) and 1.11% (0.28-1.95%), respectively, were observed among donors living in the lowest socioeconomic areas (Quintiles 1 and 2) and lowest at 0.69% (0.14-1.39%) among donors living in the highest socioeconomic areas (Quintile 5). When extrapolated to the Melbourne residential population, overall seroprevalence was 0.90% (0.26-1.51%), with estimates by demography groups similar to those for the blood donors. The results suggest a lack of extensive community transmission and good COVID-19 case ascertainment based on routine testing during Victoria's second epidemic wave. Residual blood donor samples provide a practical epidemiological tool for estimating seroprevalence and information on population patterns of infection, against which the effectiveness of ongoing responses to the pandemic can be assessed.

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.

Seroprevalence of Severe Acute Respiratory Syndrome Coronavirus 2-Specific Antibodies in Australia After the First Epidemic Wave in 2020: A National Survey.

BACKGROUND: As of mid-2021, Australia's only nationwide coronavirus disease 2019 (COVID-19) epidemic occurred in the first 6 months of the pandemic. Subsequently, there has been limited transmission in most states and territories. Understanding community spread during the first wave was hampered by initial limitations on testing and surveillance. To characterize the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody seroprevalence generated during this time, we undertook Australia's largest national SARS-CoV-2 serosurvey. METHODS: Between June 19 and August 6, 2020, residual specimens were sampled from people undergoing general pathology testing (all ages), women attending antenatal screening (20-39 years), and blood donors (20-69 years) based on the Australian population's age and geographic distributions. Specimens were tested by Wantai total SARS-CoV-2-antibody assay. Seroprevalence estimates adjusted for test performance were produced. The SARS-CoV-2 antibody-positive specimens were characterized with microneutralization assays. RESULTS: Of 11 317 specimens (5132 general pathology; 2972 antenatal; 3213 blood-donors), 71 were positive for SARS-CoV-2-specific antibodies. Seroprevalence estimates were 0.47% (95% credible interval [CrI], 0.04%-0.89%), 0.25% (CrI, 0.03%-0.54%), and 0.23% (CrI, 0.04%-0.54%), respectively. No seropositive specimens had neutralizing antibodies. CONCLUSIONS: Australia's seroprevalence was extremely low (<0.5%) after the only national COVID-19 wave thus far. These data and the subsequent limited community transmission highlight the population's naivety to SARS-CoV-2 and the urgency of increasing vaccine-derived protection.

Pertussis immunisation in infancy and atopic outcomes: A protocol for a population-based cohort study using linked administrative data.

INTRODUCTION: The burden of IgE-mediated food allergy in Australian born children is reported to be among the highest globally. This illness shares risk factors and frequently coexists with asthma, one of the most common noncommunicable diseases of childhood. Findings from a case-control study suggest that compared to immunisation with acellular pertussis vaccine, early priming of infants with whole-cell pertussis vaccine may be associated with a lower risk of subsequent IgE-mediated food allergy. If whole-cell vaccination is protective of food allergy and other atopic diseases, especially if protective against childhood asthma, the population-level effects could justify its preferential recommendation. However, the potential beneficial effects of whole-cell pertussis vaccination for the prevention of atopic diseases at a population-scale are yet to be investigated. METHODS AND ANALYSIS: Analyses of population-based record linkage data will be undertaken to compare the rates of admissions to hospital for asthma in children aged between 5 and 15 years old, who were born in Western Australia (WA) or New South Wales (NSW) between 1997 and 1999 (329,831) when pertussis immunisation in Australia transitioned from whole-cell to acellular only schedules. In the primary analysis we will estimate hazard ratios and 95% confidence intervals for the time-to-first-event (hospital admissions as above) using Cox proportional hazard models in recipients of a first dose of whole-cell versus acellular pertussis-containing vaccine before 112 days old (~4 months of age). Similarly, we will also fit time-to-recurrent events analyses using Andersen-Gill models, and robust variance estimates to account for potential within-child dependence. Hospitalisations for all-cause anaphylaxis, food anaphylaxis, venom, all-cause urticaria and atopic dermatitis will also be examined in children who received at least one dose of pertussis-containing vaccine by the time of the cohort entry, using analogous statistical methods. Presentations to the emergency departments will be assessed separately using the same statistical approach.

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.

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.

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

BACKGROUND: Risk-based recommendations are common for pneumococcal vaccines but little is known about their uptake. In Australia, pneumococcal conjugate vaccine (PCV) was funded only for Aboriginal or Torres Strait Islander (Indigenous) children and those with underlying medical conditions in 2001, and then there were different booster dose recommendations depending on risk after the introduction of universal PCV vaccination in 2005. METHODS: We measured coverage of PCV dose 3 and additional PCV and 23-valent pneumococcal polysaccharide vaccine (PPV23) doses by risk group among children born in July 2001-December 2012 in two Australian states using linked immunisation and hospitalisation data (available until December 2013). We ascertained medical risk conditions using hospitalisation diagnosis codes and Indigenous status using an established algorithm, comparing coverage for children born pre (2001-2004) and post (2005-2012) universal PCV funding. RESULTS: Among 1.3 million children, 63,897 (4.9%) were Indigenous and 32,934 (2.5%) had at least one medically at-risk condition identified by age 6 months. For births in 2001-2004, coverage for PCV dose 3 by 1 year of age was 37% for Indigenous, 15% for medically at-risk and 11% in other children, increasing to 83%, 91% and 92%, respectively for births in 2005-2012. In children with medically at-risk conditions, PCV dose 4 coverage by 2 years was 1% for 2001-2004 births, increasing to 9% for 2005-2012 births, with PPV23 coverage by 6 years 3% in both cohorts. Among eligible Indigenous children, PPV23 coverage by 3 years was 45% for 2001-2004 births and 51% for 2005-2012 births. CONCLUSIONS: Coverage with additional recommended booster doses was very low among children with medical conditions, and only modest among Indigenous children. If additional PCV doses are recommended for some risk groups, especially in the context of routine schedules with reduced doses (e.g. 2 + 1 and 1 + 1), measures to improve implementation will be required.

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.

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.

Hepatitis E as a cause of adult hospitalization in Bangladesh: Results from an acute jaundice surveillance study in six tertiary hospitals, 2014-2017.

In the absence of reliable data on the burden of hepatitis E virus (HEV) in high endemic countries, we established a hospital-based acute jaundice surveillance program in six tertiary hospitals in Bangladesh to estimate the burden of HEV infection among hospitalized acute jaundice patients aged ≥14 years, identify seasonal and geographic patterns in the prevalence of hepatitis E, and examine factors associated with death. We collected blood specimens from enrolled acute jaundice patients, defined as new onset of either yellow eyes or skin during the past three months of hospital admission, and tested for immunoglobulin M (IgM) antibodies against HEV, HBV and HAV. The enrolled patients were followed up three months after hospital discharge to assess their survival status; pregnant women were followed up three months after their delivery to assess pregnancy outcomes. From December'2014 to September'2017, 1925 patients with acute jaundice were enrolled; 661 (34%) had acute hepatitis E, 48 (8%) had hepatitis A, and 293 (15%) had acute hepatitis B infection. Case fatality among hepatitis E patients was 5% (28/589). Most of the hepatitis E cases were males (74%; 486/661), but case fatality was higher among females-12% (8/68) among pregnant and 8% (7/91) among non-pregnant women. Half of the patients who died with acute hepatitis E had co-infection with HAV or HBV. Of the 62 HEV infected mothers who were alive until the delivery, 9 (15%) had miscarriage/stillbirth, and of those children who were born alive, 19% (10/53) died, all within one week of birth. This study confirms that hepatitis E is the leading cause of acute jaundice, leads to hospitalizations in all regions in Bangladesh, occurs throughout the year, and is associated with considerable morbidity and mortality. Effective control measures should be taken to reduce the risk of HEV infections including improvements in water quality, sanitation and hygiene practices and the introduction of HEV vaccine to high-risk groups.

Infant, maternal and demographic predictors of delayed vaccination: A population-based cohort study.

BACKGROUND: Receiving vaccines at or close to their due date (vaccination timeliness) is a now key measure of program performance. However, studies comprehensively examining predictors of delayed infant vaccination are lacking. We aimed to identify predictors of short and longer-term delays in diphtheria-tetanus-pertussis (DTP) vaccination by dose number and ethnicity. METHODS: Perinatal, notification, death and immunisation databases were linked for 1.3 million births in 2000-11 from two Australian states (Western Australia and New South Wales), with follow-up data until 2013. Ordinal logistic regression was used to estimate adjusted relative risks (RR) by degree of delay. Separate models were constructed for each vaccine dose and for Aboriginal and non-Aboriginal children. RESULTS: Each dose-specific cohort included at least 49,000 Aboriginal and 1.1 million non-Aboriginal children. Delayed receipt was more common among Aboriginal than non-Aboriginal children (eg for the first dose of DTP [DTP1] 19.4 v 8.1%). Risk factors for delayed vaccination were strongest for DTP1, and delayed receipt of DTP1 was a key driver of subsequent delays; every week DTP1 was delayed was associated with a 1.6 to 2-fold increased risk of delayed DTP2 receipt. For DTP1, ≥3 previous pregnancies (the only factor more strongly associated with longer than shorter delays; RR ≥5 compared to no previous pregnancies), and children born to mothers <20 years of age (RR ≥2 compared to ≥35 years) were at highest risk of delay. Other independent predictors were prematurity, maternal smoking during pregnancy, and being born in Western Australia (if Aboriginal) or another country in the Oceania region. CONCLUSION: The sub-populations at risk for delayed vaccination we have identified are likely generalisable to other high-income settings. Measures to improve their dose 1 timeliness, particularly for children with older siblings, are likely to have significant flow-on benefits for timeliness of later doses.

Coxiella burnetii seroprevalence in unvaccinated veterinary workers in Australia: Evidence to support Q fever vaccination.

Q fever (caused by Coxiella burnetii) is a serious zoonotic disease that occurs almost worldwide. Occupational contact with animals increases the risk of exposure, and Q fever vaccination is recommended for veterinary workers in Australia. This study aimed to investigate C. burnetii seroprevalence among unvaccinated veterinary workers in Australia and determine factors associated with a positive serological result. During 2014 and 2015, convenience sampling at veterinary conferences and workplace vaccination clinics was undertaken. Participants completed a questionnaire and provided a blood sample for C. burnetii serology. Participants were predominantly veterinarians (77%), but veterinary support staff, animal scientists, and administration workers also participated. Blood samples (n = 192) were analysed by an immunofluorescence assay and considered positive where the phase I or phase II IgG titre was ≥1/50. Seroprevalence was 19% (36/192; 95% CI 14%-25%). A positive serological result was significantly associated with (a) working in outer regional/remote areas (odds ratio [OR] 6.2; 95% CI 1.9-20.8; reference = major cities; p = .009) and (b) having spent more than 50% of total career working with ruminants (OR 4.8; 95% CI 1.7-13.5; reference = <15% of career; p = .025). These findings confirm an increased risk of exposure to C. burnetii compared to the general population, providing new evidence to support Q fever vaccination of veterinary workers in Australia.