Notifiable Conditions Information Management System Research Articles

Effectiveness evaluation of digital contact tracing for COVID-19 in New South Wales, Australia

BackgroundDigital proximity tracing apps were rolled out early in the COVID-19 pandemic in many countries to complement conventional contact tracing. Empirical evidence about their benefits for pandemic response remains scarce. We evaluated the effectiveness and usefulness of COVIDSafe, Australia's national smartphone-based proximity tracing app for COVID-19.MethodsIn this prospective study, done in New South Wales (NSW), Australia, we included all individuals in the state who were older than 12 years with confirmed, locally acquired SARS-CoV-2 infection between May 4 and Nov 4, 2020. We used data from the NSW Notifiable Conditions Information Management System, the national COVIDSafe database, and information from case interviews, including information on app usage, the number of app-suggested contacts, and the number of app-suggested contacts determined by public health staff to be actual close contacts. We calculated the positive predictive value and sensitivity of COVIDSafe, its additional contact yield, and the number of averted public exposure events. Semi-structured interviews with public health staff were done to assess the app's perceived usefulness.FindingsThere were 619 confirmed COVID-19 cases with more than 25 300 close contacts identified by conventional contact tracing during the study period. COVIDSafe was used by 137 (22%) cases and detected 205 contacts, 79 (39%) of whom met the close contact definition. Its positive predictive value was therefore 39%. 35 (15%) of the 236 close contacts who could have been expected to have been using the app during the study period were identified by the app, making its estimated sensitivity 15%. 79 (0·3%) of the estimated 25 300 contacts in NSW were app-suggested and met the close contact definition. The app detected 17 (<0·1%) additional close contacts who were not identified by conventional contact tracing. COVIDSafe generated a substantial additional perceived workload for public health staff and was not considered useful.InterpretationThe low uptake of the app among cases probably led to a reduced sensitivity estimate in our study, given that only contacts who were using the app could be detected. COVIDSafe was not sufficiently effective to make a meaningful contribution to the COVID-19 response in Australia's most populous state over a 6 month period. We provide an empirical evaluation of this digital contact tracing app that questions the potential benefits of digital contact tracing apps to the public health response to COVID-19. Effectiveness evaluations should be integrated into future implementations of proximity contact tracing systems to justify their investment.FundingNew South Wales Ministry of Health (Australia); National Health and Medical Research Council (Australia)

Audit of the Sydney Local Health District Public Health Unit notification and contact tracing system during the first wave of COVID‐19

ObjectiveTo conduct a real‐time audit to assess a Continuous Quality Improvement (CQI) activity to improve the quality of public health data in the Sydney Local Health District (SLHD) Public Health Unit during the first wave of COVID‐19. MethodsA real‐time audit of the Notifiable Conditions Information Management System was conducted for positive cases of COVID‐19 and their close contacts from SLHD. After recording missing and inaccurate data, the audit team then corrected the data. Multivariable regression models were used to look for associations with workload and time. ResultsA total of 293 cases were audited. Variables measuring completeness were associated with improvement over time (p<0.0001), whereas those measuring accuracy reduced with increased workload (p=0.0003). In addition, the audit team achieved 100% data quality by correcting data. ConclusionUtilising a team, separate from operational staff, to conduct a real‐time audit of data quality is an efficient and effective way of improving epidemiological data. Implications for public healthImplementation of CQI in a public health unit can improve data quality during times of stress. Auditing teams can also act as an intervention in their own right to achieve high‐quality data at minimal cost. Together, this can result in timely and high‐quality public health data.

Drivers of the summer influenza epidemic in New South Wales, 2018-19.

To assess the extent to which the 2018-19 New South Wales summer influenza epidemic was associated with overseas or domestic travel and with seasonal influenza vaccination status. Unmatched case-control study, based on an online survey distributed from the NSW Notifiable Conditions Information Management System (NCIMS) to people for whom mobile phone numbers were available. A case was defined as a person with notified laboratory-confirmed influenza with onset of illness between 1 December 2018 and 21 March 2019. People with notified pertussis infections (confirmed or probable) were selected as controls. Notified influenza infection, by travel and contact with unwell overseas travellers in the week before onset of illness and seasonal influenza vaccination status (as the primary exposures). Valid survey responses were provided by 648 of 2806 invited people with notified influenza (23%) and 257 of 796 invited people with notified pertussis (32%). The demographic characteristics of the respondents were similar to those of the source population (7251 cases, 2254 controls). During the first two months of the summer of 2018-19, notified influenza was more likely for people who had travelled overseas or had contact with an ill overseas traveller in the week before symptom onset (adjusted OR [aOR], 6.99; 95% CI, 3.59-13.6), but not during the second two months (aOR, 1.63; 95% CI, 0.79-3.35). Influenza vaccination status was not associated with the likelihood of notified influenza. Travel-related factors were early drivers of the 2018-19 NSW summer influenza epidemic; local transmission sustained the outbreak despite unfavourable conditions later in summer. Our findings prompted re-evaluation of recommendations for pre-travel vaccination in NSW. The role of travel in out-of-season influenza outbreaks should be considered in other temperate zones.

Influenza outbreaks in aged care facilities in New South Wales in 2017: impact and lessons for surveillance.

A record number of influenza outbreaks in aged care facilities (ACFs) in New South Wales (NSW) during 2017 provided an opportunity to measure the health impact of those outbreaks and assess the quality of routinely available surveillance data. Data for all ACF influenza outbreaks in NSW in 2017 were extracted from the Notifiable Conditions Information Management System. The numbers of outbreaks, residents with influenza-like illness (ILI), hospital admissions and deaths were assessed. For each outbreak the attack rate; duration; timeliness of notification; resident and staff influenza vaccination coverage; and antiviral use for treatment or prophylaxis were analysed. Data were considered for NSW in total and separately for seven of the state's local health districts. Data completeness was assessed for all available variables. A total of 538 ACF outbreaks resulted in 7,613 residents with ILI, 793 hospitalisations and 338 deaths. NSW outbreaks had a median attack rate of 17% and median duration of eight days. Data completeness, which varied considerably between districts, limited the capacity to accurately consider some important epidemiological and policy issues. Influenza outbreaks impose a major burden on the residents and staff of ACFs. Accurate assessment of the year-to-year incidence and severity of influenza outbreaks in these facilities is important for monitoring the effectiveness of outbreak prevention and management strategies. Some key data were incomplete and strategies to improve the quality of these data are needed, particularly for: the number of influenza-related deaths among residents; resident and staff vaccination coverage prior to outbreaks; and recorded use of antiviral prophylaxis.

Hospital outcomes after a COVID-19 diagnosis from January to May 2020 in New South Wales Australia.

To describe hospitalisation rates following COVID-19 infection in NSW. Analysis of all confirmed COVID-19 cases diagnosed in NSW from 1 January to 31 May 2020 extracted from the NSW Notifiable Conditions Information Management System and linked to routinely collected hospitalisation data. In-patient hospitalisations and hospital service utilisation details. There were 3,101 COVID-19 cases diagnosed between 1 January and 31 May 2020 in NSW: mean age 46.7 years, 50.5% were females. Overall, 12.5% (n = 389) had a record of inpatient hospitalisation, 4.2% (n = 130) were admitted to ICU and 1.9% (n = 58) received ventilation. Among adult cases, hospital and ICU admission rates increased with increasing age: 2.9% of those aged 20-29 years were hospitalised, increasing to 46.6% of those aged 80-89 years; 0.6% of those aged 20-29 years were admitted to ICU, increasing to 11.2% of those aged 70-79 years. The median time from symptoms to hospitalisation was seven days (IQR 4-11). The median time in hospital was nine days (IQR 4-20), and in ICU six days (IQR 2-15); the median time in hospital increased with older age. Almost half (49.4%) of those hospitalised with a diagnostic code had pneumonia/lower respiratory tract infection and another 36.6% had an upper respiratory tract infection or other known COVID-19 symptoms. COVID-19 is a serious infection particularly in older adults. During January to May of 2020, 1 in 8 of those diagnosed in NSW were hospitalised. While this partly reflects the cautious approach to case management in the initial phase of the pandemic, it also demonstrates the large potential impact of COVID-19 on Australian health services and need for continuing mitigation strategies.

Vaccine-Preventable Infections Among Solid Organ Transplant Recipients: A Data-Linked Cohort Study, Australia, 2000-2015

IntroductionRecipients of solid organ transplants are at risk of serious infection due to immunosuppression. Some infections are preventable with vaccination; infection rates vary with immunosuppression, vaccination rates and baseline disease prevalence. Both adherence with and response to vaccination in this population are variable, and optimum vaccination strategies continue to be refined.&#x0D; Objectives and ApproachWe aimed to characterise the incidence and complications of vaccine-preventable infections in transplant recipients. Eligible participants received an organ transplant in New South Wales, Australia, in 2000-2015. Linkage was undertaken between transplant registries and the notifiable conditions information management system. Vaccine-preventable infections were diphtheria, Haemophilus influenzae type b, influenza, invasive pneumococcal disease, measles, mumps, pertussis, poliovirus, rubella and tetanus. Standardized incidence ratios (SIR) were calculated relative to Australian population notification rates, standardizing for gender, age and calendar year.&#x0D; ResultsAmong 3,394 recipients, 399 vaccine-preventable infections affected 339 (10%) recipients. Influenza was the most common vaccine-preventable infection with 352 notifications among 305 recipients. Influenza cases were 8.9 times more common among transplant recipients than the general population (95%CI: 8.0-10.0). In 36 cases (10%), hospitalization was required, and 2 deaths due to influenza were reported.&#x0D; There were 20 notifications of invasive pneumococcal disease (IPD) for 18 recipients. IPD occurred 10.2 times more often among transplant recipients than the general population (95%CI: 6.4-16.2). Most (n=13, 65%) cases were hospitalized, and one patient died from IPD.&#x0D; Cases of pertussis occurred only slightly more often than in the general population (SIR 1.5, 95%CI: 1.0-2.3). Of 26 cases, there was one reported hospitalization and no deaths due to pertussis. Only one case of mumps, and no other vaccine-preventable infections, were reported.&#x0D; ConclusionTransplant recipients have excess cases of influenza and IPD compared to the general population, although this has improved over time. The need for appropriate recipient vaccination is emphasized.

Safety and Biovigilance in Organ Donation (SAFEBOD): Protocol for a Population-Based Cohort Study.

BackgroundTension lies between the need to increase access to organ transplantation and the equally urgent need to prevent inadvertent transmission of infectious diseases or cancer from organ donors. Biovigilance, or the evaluation of potential donors, is often time-pressured and may be based on incomplete information.ObjectiveThe Safety and Biovigilance in Organ Donation (SAFEBOD) study aims to improve estimates of infection and cancer transmission risk and explore how real-time data access could support decision-making.MethodsWe will link existing donor referral, actual donor, recipient, and health-outcome data sets from 2000-2015 in New South Wales. Organ donor data sets will include the Organ Donor Characterizing Risk-Profile of Donors Study, the National Organ Matching System, the Australian and New Zealand Organ Donor Register, and the Australian and New Zealand Living Donor Kidney Register. Recipient data sets will include the Australian and New Zealand Dialysis and Transplant Register, the Australian and New Zealand Cardiothoracic Register, the Australian and New Zealand Islet and Pancreas Register, and the Australian and New Zealand Liver Transplant Register. New South Wales health outcome data sets will include HIV and AIDS Notifications and Surveillance Data, the Notifiable Conditions Information Management System, Admitted Patient Data Collection, Emergency Department Data Collection, the Central Cancer Registry, and the Cause of Death Data Collection. We will link organ donors to transplant recipients and health outcomes data sets using probabilistic data-matching based on personal identifiers. Transmission and nontransmission events will be determined by comparing previous cases in donors and posttransplant cases in recipients. We will compare the perceived-risk at referral with the verified risk from linked health outcome data sets and the odds of cancer or contracting an infectious disease in organ recipients from donors based on their transmission-risk profile and estimate recipient survival by donor transmission risk group.ResultsData were requested from each of the listed registries in September 2018, and data collection is ongoing. Linked data from all listed data sets are expected to be complete in September 2020.ConclusionsThe SAFEBOD study will overcome current limitations in organ donation by accessing comprehensive information on referred organ donors and recipients in existing data sets. The study will provide robust estimates of disease transmission and nontransmission events based on recent data. It will also describe the agreement between perceived risk estimated at the time of referral and verified risk when all health outcome data are accessible. The improved understanding of transmission and nontransmission events will inform clinical decisions and highlight where current policies can be revised to broaden the acceptance of deceased donors.International Registered Report Identifier (IRRID)DERR1-10.2196/18282

VACCINE-PREVENTABLE INFECTIONS AMONG SOLID ORGAN TRANSPLANT RECIPIENTS: A DATA-LINKED COHORT STUDY, AUSTRALIA, 2000-2015

Introduction: Infections are a common cause of morbidity and mortality among solid organ transplant recipients. Some infections are preventable with vaccination. Rates of these infections vary with immunosuppression, vaccination rates and baseline disease prevalence. Both adherence with and response to vaccination in this population are variable, and optimum vaccination strategies continue to be refined. We aimed to characterise the incidence and complications of vaccine-preventable infections in an Australian cohort of transplant recipients compared with the general population. Methods: Eligible participants received a solid organ transplant in New South Wales, Australia, in 2000-2015. Linkage was undertaken between transplant registries and the notifiable conditions information management system. Vaccine-preventable infections were laboratory confirmed diphtheria, Haemophilus influenzae type b, influenza, invasive pneumococcal disease, measles, mumps, pertussis, poliovirus, rubella and tetanus. Extracted information included infection type, date, clinical site, hospitalizations and deaths due to infection. Crude incidence rates were calculated for each infection from transplant date censored at first infection episode, death, loss to follow up or end of observation period (Dec 2016). Standardized incidence ratios (SIR) were calculated relative to Australian population notification rates, standardizing for gender, age (5-year categories) and calendar year. Results: Among 3,394 eligible recipients, 399 vaccine-preventable infections affected 339 (10%) recipients. Influenza was the most common vaccine-preventable infection with 352 notifications among 305 recipients. Influenza cases were much more common among transplant recipients than the general population (SIR 8.9, 95% CI 8.0-10.0, Table 1). In 36 cases (10%), hospitalization was required, and 2 deaths due to influenza were reported.There were 20 notifications of invasive pneumococcal disease (IPD) for 18 recipients. IPD occurred 10.2 times more often among transplant recipients than the general population (95%CI: 6.4-16.2). Most (n=13, 65%) cases were hospitalized, and one patient died from invasive pneumococcal disease. The excess burden of both influenza and IPD decreased over time (Figure 1).Cases of pertussis occurred only slightly more often than in the general population (SIR 1.5, 95%CI: 1.0-2.3). Of 26 cases, there was one reported hospitalization and no deaths due to pertussis. Only one case of mumps, and no other vaccine-preventable infections, were reported. Conclusion: Influenza and IPD occur more frequently among organ transplant recipients than the general population, with appreciable morbidity and mortality. Excess rates of influenza and IPD have decreased over time, which may reflect improvements in vaccination. Other vaccine-preventable infections were not associated with excess disease among transplant recipients. The need for appropriate recipient vaccination is emphasized. NSW Ministry of Health. NHMRC Postgraduate Scholarship GNT1168202.

231.1: Assessment of blood borne viruses risk in organ donation: Use of linked health data to identify missed opportunities and transmissions in an Australian cohort.

Background: Organ donor referrals may be declined when social or medical history suggests increased risk of blood borne virus (BBV) transmission, although this information can be limited. Inaccurate risk assessments can lead to either missed opportunities for donation, or transmission of BBV to recipients. We aimed to identify potential missed opportunities, when referrals were declined due to perceived BBV risk, and BBV transmissions via transplantation. Methods: We used the New South Wales (NSW) Biovigilance Public Health Register, SAFEBOD. This register linked donor referrals in NSW to administrative health databases, including hospital admissions data, notifiable conditions information management system and the death register. For missed opportunities, we examined BBV diagnoses in linked health data for donor referrals (2010-2015) who did not donate due to perceived increased viral risk for HIV, Hepatitis B (HBV) and Hepatitis C (HCV); this included those with active or past infection (based on serology or medical report), or high risk behaviour at referral. For transmissions, we examined donor-recipient pairs 2000-2015 for new BBV diagnoses in linked-health data within 12 months after transplant, and classified transmissions using a standardised algorithm (Green, 2015). Results: Of 2,961 persons referred for organ donation in NSW (2010-2015), there were 1,164 persons eligible for donation. 165 persons did not donate due to perceived increased BBV risk (Figure 1), and 33 of these 165 (20%) had no evidence of any BBV infection up to their terminal contact with health services. In NSW (2000-2015), 2,194 organ donors donated 3,940 organs to 2765 recipients. 2,096 donors had baseline BBV transmission risk and 98 had increased BBV transmission risk. There were 3 proven/probable transmission events (2 HBV, 1 HCV), all from donors with active or past BBV (Figure 2). There were no deaths due to transmissions. Conclusions: BBV risk assessments are largely accurate with few transmissions but up to 20% rejected referrals may be missed opportunities. Routinely collected administrative health data may provide a useful additional information source to aid decision-making.

Vaccine-preventable child deaths in New South Wales from 2005 to 2014: How much is preventable?

To identify and describe potentially vaccine-preventable child deaths in New South Wales (NSW). Child deaths in NSW from 2005 to 2014 potentially preventable by vaccination were identified from the NSW Child Death Register (maintained by the NSW Ombudsman) and the Notifiable Conditions Information Management System (NSW Health). Medical and post-mortem records were reviewed. Cases were classified as vaccine-preventable based on the strength of evidence for the relevant infection causing death and likelihood that death was preventable through vaccination. A two-source capture-recapture method was used to estimate the true number of deaths. Age-specific mortality rate and number of deaths by disease, area of residence and comorbidity were analysed. Deaths were classified as preventable based on vaccine availability, eligibility under the National Immunisation Program, age and presence of any contraindications. Fifty-four deaths were identified as definitely or probably due to diseases for which a vaccine was available, with a total average annual mortality rate of 0.33 per 100 000 children and 2.1 per 100 000 infants. Two thirds of deaths occurred in children with no identified comorbidities. Twenty-three deaths were classified as preventable or potentially preventable by vaccination, with influenza (12 deaths) and meningococcal disease (five deaths) most common. An additional 15 deaths would be potentially preventable as of August 2016 due to immunisation recommendation changes including maternal vaccination. Maternal vaccination along with increased uptake of childhood influenza vaccination could reduce child deaths, particularly from influenza.

Monitoring travellers from Ebola-affected countries in New South Wales, Australia: what is the impact on travellers?

BackgroundAmidst an Ebola virus disease (EVD) epidemic of unprecedented magnitude in west Africa, concerns about the risk of importing EVD led to the introduction of programs for the screening and monitoring of travellers in a number of countries, including Australia. Emerging reports indicate that these programs are feasible to implement, however rigorous evaluations are not yet available. We aimed to evaluate the program of screening and monitoring travellers in New South Wales.MethodsWe conducted a mixed methods study to evaluate the program of screening and monitoring travellers in New South Wales. We extracted quantitative data from the Notifiable Conditions Information Management System database and obtained qualitative data from two separate surveys of public health staff and arrivals, conducted by phone.ResultsBetween 1 October 2014 and 13 April 2015, public health staff assessed a total of 122 out of 123 travellers. Six people (5%) developed symptoms compatible with EVD and required further assessment. None developed EVD. Aid workers required lower levels of support compared to other travellers. Many travellers experienced stigmatisation. Public health staff were successful in supporting travellers to recognise and manage symptoms.ConclusionWe recommend that programs for monitoring travellers should be tailored to the needs of different populations and include specific strategies to remediate stigmatisation.

Effect of antiviral prophylaxis on influenza outbreaks in aged care facilities in three local health districts in New South Wales, Australia, 2014.

There was a record number (n=111) of influenza outbreaks in aged care facilities in New South Wales, Australia during 2014. To determine the impact of antiviral prophylaxis recommendations in practice, influenza outbreak data were compared for facilities in which antiviral prophylaxis and treatment were recommended and for those in which antivirals were recommended for treatment only. Routinely collected outbreak data were extracted from the Notifiable Conditions Information Management System for two Local Health Districts where antiviral prophylaxis was routinely recommended and one Local Health District where antivirals were recommended for treatment but not routinely for prophylaxis. Data collected on residents included counts of influenza-like illness, confirmed influenza, hospitalizations and related deaths. Dates of onset, notification, influenza confirmation and antiviral recommendations were also collected for analysis. The Mann-Whitney U test was used to assess the significance of differences between group medians for key parameters. A total of 41 outbreaks (12 in the prophylaxis group and 29 in the treatment-only group) were included in the analysis. There was no significant difference in overall outbreak duration; outbreak duration after notification; or attack, hospitalization or case fatality rates between the two groups. The prophylaxis group had significantly higher cases with influenza-like illness (P=0.03) and cases recommended antiviral treatment per facility (P=0.01). This study found no significant difference in key outbreak parameters between the two groups. However, further high quality evidence is needed to guide the use of antivirals in responding to influenza outbreaks in aged care facilities.

New South Wales annual vaccine-preventable disease report, 2013

To describe the epidemiology of selected vaccine-preventable diseases in New South Wales, Australia for 2013. Data from the New South Wales Notifiable Conditions Information Management System were analysed by local health district of residence, age, Aboriginality, vaccination status and organism. Risk factor and vaccination status data were collected by public health units. Pertussis notification rates in infants were low, and no infant pertussis deaths were reported. Despite a high number of imported measles cases, there was limited secondary transmission. The invasive meningococcal disease notification rate declined, and disease due to serogroup C remained low and stable. Vaccine-preventable diseases were relatively well controlled in New South Wales in 2013, with declining or stable notification rates in most diseases compared with the previous year.

New South Wales annual vaccine-preventable disease report, 2012.

We aim to describe the epidemiology of selected vaccine-preventable diseases in New South Wales (NSW) for 2012. Data from the NSW Notifiable Conditions Information Management System were analysed by: local health district of residence, age, Aboriginality, vaccination status and organism, where available. Risk factor and vaccination status data were collected by public health units for cases following notification under the NSW Public Health Act 2010. The largest outbreak of measles since 1998 was reported in 2012. Pacific Islander and Aboriginal people were at higher risk as were infants less than 12 months of age. Notifications of invasive pneumococcal disease (IPD) in children less than fiveyears declined; however, the overall number of notifications for IPD increased. Mumps case notifications were also elevated. There were no Haemophilus influenzae type b case notifications in children less than fiveyears of age for the first time since the vaccine was introduced. Invasive meningococcal disease case notifications were at their lowest rates since case notification began in 1991. Case notification rates for other selected vaccine-preventable diseases remained stable. Vaccine-preventable disease control is continually strengthening in NSW with notable successes in invasive bacterial infections. However, strengthening measles immunization in Pacific Islander and Aboriginal communities remains essential to maintain measles elimination.

Infectious diseases in returned travellers, NSW, 2010-2011.

To quantify the proportion of selected notified diseases in NSW attributable to overseas travel and assess the quality of data on travel-associated risk factors, to inform prevention strategies. 2010 and 2011 notification data for dengue, hepatitis A, hepatitis E, malaria, paratyphoid fever, shigellosis and typhoid fever were extracted from the NSW Notifiable Conditions Information Management System and analysed for travel-associated risk factors. Where place of acquisition was known, the proportion of cases for whom the disease was acquired overseas ranged from 48.7% for shigellosis to 100% for hepatitis E, malaria and typhoid. Over half of hepatitis A (53.3%), hepatitis E (74.2%), malaria (54.5%), paratyphoid (53.3%) and typhoid (65.7%) cases were associated with travel to the person's country of birth. Hepatitis A vaccination rates were significantly lower among overseas-acquired than locally-acquired cases (4.8% vs 22.2%, Χ(2)=6.58, p<0.02). A large proportion of selected enteric and vectorborne disease case notifications were associated with overseas travel. All potential travellers should be made aware of the risks and available preventive measures, such as vaccination against hepatitis A and typhoid fever, taking precautions with food and water and use of malaria chemoprophylaxis, where appropriate. Improvements in data on risk factors, reason for travel and barriers to the use of preventive measures would better inform prevention strategies.

Tuberculosis, public health and gathering new evidence to guide control efforts

Aim: To describe the epidemiology of tuberculosis in NSW between 2009 and 2011 and comparewith previous years.Methods:Data from all cases of tuberculosis notified in NSW during this period were extracted from the Notifiable Conditions Information Management System. Descriptive analyses of notification data were undertaken. Incidence rates were calculated per 100 000 population. Results: Between 2009 and 2011, there were 1548 cases of tuberculosis notified in NSW, translating to an average annual notification rate of 7.2 per 100 000 population for this period. A total of 89% (n1⁄4 1371) of notified cases were overseas-born, and 1.6% (n1⁄4 24) of cases were recorded as Aboriginal persons. The most common site of infection was the lung (60% of cases). Of notified cases, 68% were reported as having been tested for HIV, of which 3% (n1⁄4 28) of cases had HIV/tuberculosis co-infection. There were 20 cases of multidrug-resistant tuberculosis, including one case of extensively drug-resistant tuberculosis. Conclusion: The notification rate of tuberculosis in NSW has remained relatively stable over the past two decades, though small incremental increases since 2003 are evident. Endemic transmission of tuberculosis within subgroups of the NSW population, as well as the ongoing high endemnicity for tuberculosis in neighbouring countries, highlight the importance of tuberculosis control as a continued strategic priority for disease control in NSW. Tuberculosis (TB) remains a disease of global public health significance. The World Health Organization (WHO) estimates that in 2011 there were 8.7 million incident cases of TB and 1.4 million TB-related deaths, as well as an additional 430 000 deaths as a result of TB and human immunodeficiency virus (HIV) co-infection. In Australia the incidence of TB is low: in 2010 it was reported by WHO to be 6.1 cases per 100 000 population. Mortality from TB, excluding HIV-positive cases, was less than one TB-related death per 100 000 population in Australia in 2010. Despite Australia’s low incidence, TB control remains a challenge as the epidemiology of this disease must be considered in a global context given the frequency of international travel and migration from high-incidence countries. The incidence and prevalence of TB in many of Australia’s international neighbours remains high. Twenty-two countries account for 80% of the global burden of TB; nine of these countries are within the South-East Asian and Western Pacific Regions. These two regions also account for approximately 18% of multidrug-resistant TB (MDR-TB) cases. Given the global context of TB epidemiology, elimination of disease within any given country is not considered feasible. The key goals and strategies of the New South Wales (NSW) TB Control Program therefore focus on case finding, early diagnoses and effective treatment in order to minimise and eliminate local transmission. NSW has a strong surveillance system in place, whereby all patients diagnosed with TB are notified to a public health unit or chest clinic in accordance with the NSW Public Health Act 2010. Case details are then entered into a central registry, the Notifiable Conditions Information Management System. The aim of this report is to describe the epidemiology of TB in NSW between 2009 and 2011 by examining the demographic and clinical characteristics, and risk factors for infection, of notified cases. We report on the public health follow-up of cases and the extent of contact tracing activities undertaken by public health and clinical services. We also compare incidence data with data from previous years. Understanding the epidemiology of TB in NSW is critical for informing and evaluating disease control strategies. Methods Data sources TB notification data were extracted from the Notifiable Conditions Information Management System. Data were included in the study when the year of diagnosis was between 2009 and 2011 (inclusive). Population data including NSW mid-year population estimates, estimated populations by country of birth and population estimates by Local Health District (LHD) were obtained from the 10.1071/NB12115 Vol. 24(1) 2013 NSW Public Health Bulletin | 3 EPIREVIEW

EpiReview: Typhoid fever, NSW, 2005–2011

To examine trends in the incidence of typhoid fever in NSW to inform the development of prevention strategies. Typhoid fever case notification data for the period 2005-2011 were extracted from the NSW Notifiable Conditions Information Management System. Population incidence rates were calculated and analysed by demographic variables. There were 250 case notifications of typhoid fever in NSW from 2005 to 2011, of which 240 are likely to have been acquired overseas. Case notifications remained relatively stable over the review period with the highest rates in Western Sydney Local Health District (10.9 per 100,000 population). Two-thirds (66.4%) of all case notifications are likely to have been acquired in South Asia, and about half of overseas-acquired case notifications were most likely to have been associated with travel to visit friends and relatives. Hospitalisation was required for 79.6% of cases where hospitalisation status was known. Prior typhoid vaccination was reported in 7% of cases in 2010 and 2011 where vaccination status was known. While typhoid fever rates remain low in NSW, case notifications of this preventable infection continue to be reported, particularly in travellers visiting friends and relatives in South Asia. Further research to better understand barriers to the use of preventive measures may be useful in targeting typhoid fever prevention messages in high-risk groups, particularly South Asian communities in NSW.

EpiReview: Tuberculosis in NSW, 2009?2011

To describe the epidemiology of tuberculosis in NSW between 2009 and 2011 and compare with previous years. Data from all cases of tuberculosis notified in NSW during this period were extracted from the Notifiable Conditions Information Management System. Descriptive analyses of notification data were undertaken. Incidence rates were calculated per 100000 population. Between 2009 and 2011, there were 1548 cases of tuberculosis notified in NSW, translating to an average annual notification rate of 7.2 per 100000 population for this period. A total of 89% (n=1371) of notified cases were overseas-born, and 1.6% (n=24) of cases were recorded as Aboriginal persons. The most common site of infection was the lung (60% of cases). Of notified cases, 68% were reported as having been tested for HIV, of which 3%(n=28) of cases had HIV/tuberculosis co-infection. There were 20 cases of multidrug-resistant tuberculosis, including one case of extensively drug-resistant tuberculosis. The notification rate of tuberculosis in NSW has remained relatively stable over the past two decades, though small incremental increases since 2003 are evident. Endemic transmission of tuberculosis within sub-groups of the NSW population, as well as the ongoing high endemnicity for tuberculosis in neighbouring countries, highlight the importance of tuberculosis control as a continued strategic priority for disease control in NSW.

Surveillance should be strengthened to improve epidemiological understandings of mosquito-borne Barmah Forest virus infection

Barmah Forest virus (BFV) is a mosquito-borne virus causing epidemic polyarthritis in Australia. This study used case follow-up of cases from the surveillance system to demonstrate that routinely collected BFV notification data were an unreliable indicator of the true location of exposure. BFV notifications from June 2001 to May 2011 were extracted from the New South Wales (NSW) Notifiable Conditions Information Management System to study case distribution. Disease cluster analysis was performed using spatial scan statistics. Exposure history data were collected from cases notified in 2010 and 2011 to accurately determine travel to high-risk areas. Cluster analysis using address data identified an area of increased BFV disease incidence in the mid-north coast of NSW contiguous with estuarine wetlands. When travel to this area was investigated, 96.7% (29/30) cases reported having visited coastal regions within four weeks of developing symptoms. Along the central NSW coastline, extensive wetlands occur in close proximity to populated areas. These wetlands provide ideal breeding habitats for a range of mosquito species implicated in the transmission of BFV. This is the first study to fully assess case exposure with findings suggesting that sporadic cases of BFV in people living further away from the coast do not reflect alternative exposure sites but are likely to result from travel to coastal regions. Spatial analysis by case address alone may lead to inaccurate understandings of the true distribution of arboviral diseases. Subsequently, this information has important implications for the collection of mosquito-borne disease surveillance information and public health response strategies.

NSW Annual Vaccine-Preventable Disease Report, 2011

To describe the epidemiology of selected vaccine-preventable diseases in NSW for 2011. Data from the NSW Notifiable Conditions Information Management System were analysed by: local health district of residence, age, Aboriginality, vaccination status, and organism, where available. Risk factor and vaccination status data were collected by public health units for case-patients following notification under the NSW Public Health Act 1991*. Outbreaks of measles and pertussis were reported in 2011, associated with unimmunised groups for measles, and a variety of factors for pertussis. Notification rates for other selected vaccine-preventable diseases remained stable. Vaccine-preventable diseases are generally well controlled in NSW. However, pertussis remains an important public health issue. To prevent measles high population vaccination coverage, including vaccination in risk groups, is essential.