Amalie Dyda

Epidemiology of Shiga toxin producing Escherichia coli in Australia, 2000-2010

BackgroundShiga toxin-producing Escherichia coli (STEC) are an important cause of gastroenteritis in Australia and worldwide and can also result in serious sequelae such as haemolytic uraemic syndrome (HUS). In this paper we describe the epidemiology of STEC in Australia using the latest available data.MethodsNational and state notifications data, as well as data on serotypes, hospitalizations, mortality and outbreaks were examined.ResultsFor the 11 year period 2000 to 2010, the overall annual Australian rate of all notified STEC illness was 0.4 cases per 100,000 per year. In total, there were 822 STEC infections notified in Australia over this period, with a low of 1 notification in the Australian Capital Territory (corresponding to a rate of 0.03 cases per 100,000/year) and a high of 413 notifications in South Australia (corresponding to a rate of 2.4 cases per 100,000/year), the state with the most comprehensive surveillance for STEC infection in the country. Nationally, 71.2% (504/708) of STEC infections underwent serotype testing between 2001 and 2009, and of these, 58.0% (225/388) were found to be O157 strains, with O111 (13.7%) and O26 (11.1%) strains also commonly associated with STEC infections. The notification rate for STEC O157 infections Australia wide between 2001-2009 was 0.12 cases per 100,000 per year. Over the same 9 year period there were 11 outbreaks caused by STEC, with these outbreaks generally being small in size and caused by a variety of serogroups. The overall annual rate of notified HUS in Australia between 2000 and 2010 was 0.07 cases per 100,000 per year. Both STEC infections and HUS cases showed a similar seasonal distribution, with a larger proportion of reported cases occurring in the summer months of December to February.ConclusionsSTEC infections in Australia have remained fairly steady over the past 11 years. Overall, the incidence and burden of disease due to STEC and HUS in Australia appears comparable or lower than similar developed countries.

Epidemiology of chlamydia and gonorrhoea among Indigenous and non-Indigenous Australians, 2000-2009.

Objectives: To assess notification trends for chlamydia and gonorrhoea infections in Indigenous Australians compared with non‐Indigenous Australians in 2000–2009.

Coinfection with Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis: a cross-sectional analysis of positivity and risk factors in remote Australian Aboriginal communities

Objectives To determine the co-occurrence and epidemiological relationships of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV) in a high-prevalence setting in Australia. Methods In the context of a cluster randomised trial in 68 remote Aboriginal communities, we obtained laboratory reports on simultaneous testing for CT, NG and TV by nucleic acid amplification tests in individuals aged ≥16 years and examined relationships between age and sex and the coinfection positivity. ORs were used to determine which infections were more likely to co-occur by demographic category. Results Of 13 480 patients (median age: 30 years; men: 37%) tested for all three infections during the study period, 33.3% of women and 21.3% of men had at least one of them, highest in patients aged 16–19 years (48.9% in women, 33.4% in men). The most frequent combination was CT/NG (2.0% of women, 4.1% of men), and 1.8% of women and 0.5% of men had all three. In all co-combinations, coinfection positivity was highest in patients aged 16–19 years. CT and NG were highly predictive of each others presence, and TV was associated with each of the other two infections, but much more so with NG than CT, and its associations were much stronger in women than in men. Conclusions In this remote high-prevalence area, nearly half the patients aged 16–19 years had one or more sexually transmitted infections. CT and NG were more common dual infections. TV was more strongly associated with NG coinfections than with CT. These findings confirm the need for increased simultaneous screening for CT, NG and TV, and enhanced control strategies. Trial registration Australian and New Zealand Clinical Trials Registry ACTRN12610000358044.

Incidence of curable sexually transmissible infections among adolescents and young adults in remote Australian Aboriginal communities: analysis of longitudinal clinical service data

Objectives To undertake the first comprehensive analysis of the incidence of three curable sexually transmissible infections (STIs) within remote Australian Aboriginal populations and provide a basis for developing new control initiatives. Methods We obtained all results for Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV) testing conducted during 2009–2011 in individuals aged ≥16 years attending 65 primary health services across central and northern Australia. Baseline prevalence and incidence of all three infections was calculated by sex and age group. Results A total of 17 849 individuals were tested over 35 months. Baseline prevalence was 11.1%, 9.5% and 17.6% for CT, NG and TV, respectively. During the study period, 7171, 7439 and 4946 initially negative individuals had a repeat test for CT, NG and TV, respectively; these were followed for 6852, 6981 and 6621 person-years and 651 CT, 609 NG and 486 TV incident cases were detected. Incidence of all three STIs was highest in 16-year-olds to 19-year-olds compared with 35+ year olds (incident rate ratio: CT 10.9; NG 11.9; TV 2.5). In the youngest age group there were 23.4 new CT infections per 100 person-years for men and 29.2 for women; and 26.1 and 23.4 new NG infections per 100 person-years in men and women, respectively. TV incidence in this age group for women was also high, at 19.8 per 100 person-years but was much lower in men at 3.6 per 100 person-years. Conclusions This study, the largest ever reported on the age and sex specific incidence of any one of these three curable infections, has identified extremely high rates of new infection in young people. Sexual health is a priority for remote communities, but will clearly need new approaches, at least intensification of existing approaches, if a reduction in rates is to be achieved.

Factors associated with influenza vaccination in middle and older aged Australian adults according to eligibility for the national vaccination program

BACKGROUND In Australia, influenza vaccination is recommended and provided free of charge for all adults aged ≥65 years and those aged <65 years with specific risk factors. Other than age, there is limited information on characteristics associated with vaccine uptake. METHODS We used the 45 and Up Study, a large cohort of adults aged ≥45 years, who completed a questionnaire in 2012 asking about influenza vaccination. We compared characteristics of those reporting influenza vaccination in those aged <65 and ≥65 years using a log binomial model to estimate relative rates (RRs), adjusted for age and other factors. RESULTS Among 27,036 participants, the proportion reporting influenza vaccination in the last year increased steadily with age from 24.6% in those <54 years to 67.2% in those 75-79 years; of those eligible for universal free vaccine, (≥65 years) 57.3% had an influenza vaccination in the previous year. Many characteristics associated with higher vaccination rates in adults aged <65 years (mean 60.7) and those ≥65 years (mean 73.7) were similar. These included sex (women versus men: <65 years, aRR=1.14[95% CI 1.08-1.20]; ≥65 years, aRR=1.04[1.02-1.07]), higher BMI (≥30 kg/m(2) versus >18.5 to <25 kg/m(2): <65 years, aRR=1.16[1.09-1.24]; ≥65 years, aRR=1.06[1.03-1.09]), requiring assistance with daily tasks versus not (<65 years, aRR=1.27[1.15-1.40]; ≥65 years, aRR=1.05[1.02-1.09]) and reporting versus not reporting specific chronic illnesses (<65 years, aRR=1.55 [1.48-1.63]; ≥65 years, aRR=1.08[1.06-1.10]). Current smokers had lower vaccination rates (<65 years, aRR=0.78[0.69-0.90]; ≥65 years, aRR=0.91[0.84-0.99]). Among those aged <65 years only, being a carer, higher income, and education were associated with influenza vaccination (aRR=1.32[1.19-1.47], 1.17[1.10-1.24] and 1.12[1.10-1.22] respectively). Non-English speaking country of birth was associated with lower vaccination rates in ≥65 years (aRR 0.86[0.81-0.92]). CONCLUSIONS Factors most strongly associated with vaccination were age and among those aged <65 years, having a medical indication recommended for influenza vaccination, suggesting higher uptake among those who can access free vaccine. Among those eligible for free vaccination, interventions could be targeted towards men, smokers, those from non-English speaking backgrounds and those <65 years with a medical indication.

Comparative epidemiology of Middle East respiratory syndrome coronavirus (MERS-CoV) in Saudi Arabia and South Korea

MERS-CoV infection emerged in the Kingdom of Saudi Arabia (KSA) in 2012 and has spread to 26 countries. However, 80% of all cases have occurred in KSA. The largest outbreak outside KSA occurred in South Korea (SK) in 2015. In this report, we describe an epidemiological comparison of the two outbreaks. Data from 1299 cases in KSA (2012–2015) and 186 cases in SK (2015) were collected from publicly available resources, including FluTrackers, the World Health Organization (WHO) outbreak news and the Saudi MOH (MOH). Descriptive analysis, t-tests, Chi-square tests and binary logistic regression were conducted to compare demographic and other characteristics (comorbidity, contact history) of cases by nationality. Epidemic curves of the outbreaks were generated. The mean age of cases was 51 years in KSA and 54 years in SK. Older males (⩾70 years) were more likely to be infected or to die from MERS-CoV infection, and males exhibited increased rates of comorbidity in both countries. The epidemic pattern in KSA was more complex, with animal-to-human, human-to-human, nosocomial and unknown exposure, whereas the outbreak in SK was more clearly nosocomial. Of the 1186 MERS cases in KSA with reported risk factors, 158 (13.3%) cases were hospital associated compared with 175 (94.1%) in SK, and an increased proportion of cases with unknown exposure risk was found in KSA (710, 59.9%). In a globally connected world, travel is a risk factor for emerging infections, and health systems in all countries should implement better triage systems for potential imported cases of MERS-CoV to prevent large epidemics.

Barriers and facilitators of sexually transmissible infection testing in remote Australian Aboriginal communities: results from the Sexually Transmitted Infections in Remote Communities, Improved and Enhanced Primary Health Care (STRIVE) Study.

UNLABELLED Background Remote Australian Aboriginal communities experience high rates of bacterial sexually transmissible infections (STI). A key strategy to reduce STIs is to increase testing in primary health care centres. The current study aimed to explore barriers to offering and conducting STI testing in this setting. METHODS A qualitative study was undertaken as part of the STI in Remote communities, Improved and Enhanced Primary Health Care (STRIVE) project; a large cluster randomised controlled trial of a sexual health quality improvement program. We conducted 36 in-depth interviews in 22 participating health centres across four regions in northern and central Australia. RESULTS Participants identified barriers including Aboriginal cultural norms that require the separation of genders and traditional kinship systems that prevent some staff and patients from interacting, both of which were exacerbated by a lack of male staff. Other common barriers were concerns about client confidentiality (lack of private consulting space and living in small communities), staff capacity to offer testing impacted by the competing demands for staff time, and high staff turnover resulting in poor understanding of clinic systems. Many participants also expressed concerns about managing positive test results. To address some of these barriers, participants revealed informal strategies, such as team work, testing outside the clinic and using adult health checks. CONCLUSIONS Results identify cultural, structural and health system issues as barriers to offering STI testing in remote communities, some of which were overcome through the creativity and enthusiasm of individuals rather than formal systems. Many of these barriers can be readily addressed through strengthening existing systems of cultural and clinical orientation and educating staff to view STI in a population health framework. However others, particularly issues in relation to culture, kinship ties and living in small communities, may require testing modalities that do not rely on direct contact with health staff or the clinic environment.

Text message reminders do not improve hepatitis B vaccination rates in an Australian sexual health setting

OBJECTIVE To evaluate the impact of text message reminders (short messaging service (SMS)) on hepatitis B virus (HBV) vaccination completion among high risk sexual health center attendees. MATERIALS AND METHODS In September 2008, Sydney Sexual Health Centre implemented an SMS reminder system. The authors assessed the impact of the reminder system on HBV vaccination rates among patients who initiated a course. The authors used a chi-square test and multivariate logistic regression to determine if SMS reminders were associated with second and third dose vaccine completion, compared with patients prior to the intervention. RESULTS Of patients sent SMS reminders in 2009 (SMS group), 54% (130/241) received 2 doses and 24% (58/241) received 3 doses, compared to 56% (258/463) (P = 0.65) and 30% (141/463) (P = 0.07) in the pre-SMS group (2007), respectively. Findings did not change after adjusting for baseline characteristics significantly different between study groups. There were no significant differences in completion rates among people who injected drugs, HIV-negative gay and bisexual men (GBM), and HIV-positive GBM. Among sex workers, travelers, and people who reported sex overseas, second and third dose completion rates were significantly lower in the SMS group compared to the pre-SMS group. In the SMS group, 18% of those who only had one dose attended the clinic within 1-18 months and 30% of those who had 2 doses attended in 6-18 months, but vaccination was missed. DISCUSSION SMS reminders did not increase second or third vaccine dose completion in this population. CONCLUSION Clinician prompts to reduce missed opportunities and multiple recall interventions may be needed to increase HBV vaccination completion in this high risk population.

Does Zika Virus Cause Microcephaly - Applying the Bradford Hill Viewpoints

Introduction: Zika virus has been documented since 1952, but been associated with mild, self-limiting disease. Zika virus is classified as an arbovirus from a family of Flaviviridae and primarily spread by Aedes Aegypti mosquitos. However, in a large outbreak in Brazil in 2015, Zika virus has been associated with microcephaly. Methods: In this review we applied the Bradford-Hill viewpoints to investigate the association between Zika virus and microcephaly. We examined historical studies, available data and also compared historical rates of microcephaly prior to the Zika virus outbreak. The available evidence was reviewed against the Bradford Hill viewpoints. Results: All the nine criteria were met to varying degrees: strength of association, consistency of the association, specificity, temporality, plausibility, coherence, experimental evidence, biological gradient and analogy. Conclusion: Using the Bradford Hill Viewpoints as an evaluation framework for causation is highly suggestive that the association between Zika virus and microcephaly is causal. Further studies using animal models on the viewpoints which were not as strongly fulfilled would be helpful.

Comparison of influenza vaccination coverage between immigrant and Australian-born adults

Australia has a large immigrant population but there are few data regarding whether influenza vaccine coverage in adults varies according to country of birth. We quantified and compared self-reported influenza vaccination coverage between Australian-born and immigrant residents aged ⩾49years enrolled in a large cohort (the 45 and Up Study), surveyed in 2012 and 2013. Estimated vaccine coverage was adjusted for age, sex and other factors known to be associated with vaccine uptake. Among 76,040 participants included in the analyses (mean age 66.2years), 21.6% were immigrants. In Australian-born adults aged 49-64 and 65+ years the age- and sex-adjusted estimates for influenza vaccination within the year prior to survey was 39.5% (95% CI 38.9-40.0) and 70.9% (70.4-71.5) respectively. The corresponding estimates in immigrants were significantly lower at 34.8% (33.7-35.8) and 64.4% (63.4-65.4) respectively. Among immigrants, coverage varied by region of birth, and was slightly lower among those who spoke a language other than English at home compared to those who only spoke English. Among immigrants there was no significant difference in coverage comparing those who migrated when they were children to those who migrated as adults and coverage did not differ significantly according to years lived in Australia. Programs to increase adult vaccination coverage should consider the needs of immigrants.