ABSTRACT
The mechanisms driving dynamics of many epidemiologically important mosquito-borne pathogens are complex, involving combinations of vector and host factors (e.g., species composition and life-history traits), and factors associated with transmission and reporting. Understanding which intrinsic mechanisms contribute most to observed disease dynamics is important, yet often poorly understood. Ross River virus (RRV) is Australia's most important mosquito-borne disease, with variable transmission dynamics across geographic regions. We used deterministic ordinary differential equation models to test mechanisms driving RRV dynamics across major epidemic centers in Brisbane, Darwin, Mandurah, Mildura, Gippsland, Renmark, Murray Bridge, and Coorong. We considered models with up to two vector species (Aedes vigilax, Culex annulirostris, Aedes camptorhynchus, Culex globocoxitus), two reservoir hosts (macropods, possums), seasonal transmission effects, and transmission parameters. We fit models against long-term RRV surveillance data (1991-2017) and used Akaike Information Criterion to select important mechanisms. The combination of two vector species, two reservoir hosts, and seasonal transmission effects explained RRV dynamics best across sites. Estimated vector-human transmission rate (average ß = 8.04x10-4per vector per day) was similar despite different dynamics. Models estimate 43% underreporting of RRV infections. Findings enhance understanding of RRV transmission mechanisms, provide disease parameter estimates which can be used to guide future research into public health improvements and offer a basis to evaluate mitigation practices.
Subject(s)
Aedes , Alphavirus Infections , Culex , Animals , Humans , Ross River virus , Alphavirus Infections/epidemiology , Mosquito Vectors , Australia/epidemiologyABSTRACT
BACKGROUND AND AIM: Pregnancy is a key setting for engagement in chronic hepatitis B (CHB) care, due to the implications for transmission to the infant and antenatal diagnosis representing an opportunity for ongoing follow-up. This study aimed to identify the coverage and predictors of clinical care for women with CHB during and after pregnancy in a population-level cohort. METHODS: Notified CHB cases in Victoria, Australia, were linked with hospitalizations, medical services, and prescribing data, covering the period 1991-2018. Women with an admission for a live birth were identified and services provided during pregnancy were assessed, including general practitioner (GP) or specialist visits, viral load and serology testing, and antiviral treatment. Viral load and serology testing coverage ware also assessed for the 2-year period following pregnancy. Demographic and clinical predictors of viral load testing during pregnancy were assessed. RESULTS: A total of 11 015 birth events occurred for 6090 women with CHB. During pregnancy most had a GP consultation (91.6%); however, only 39.5% had viral load testing and 41.4% had a gastroenterology or infectious diseases specialist consultation. Viral load testing and serology testing in the 2 years after pregnancy occurred in approximately half (47.9% and 52.2%, respectively) with increases over time. Viral load testing was more likely in those born overseas, those with more than one previous birth, and those living in Melbourne. CONCLUSIONS: Despite improvements over time, key gaps were identified in the provision of CHB clinical care during and after pregnancy, with implications for ongoing transmission and adverse outcomes.
ABSTRACT
BACKGROUND: Highly effective hepatitis C therapies are available in Australia. However, people living with hepatitis C face various barriers to accessing care and treatment. AIMS: To identify gaps in the cascade of care for hepatitis C and generate estimates of the number living with untreated infection according to population group, using a representative longitudinal study population. METHODS: We linked hepatitis C notification data from Victoria to national pathology, prescribing and death registry data. We assessed receipt of key clinical services in a large cohort who tested positive for hepatitis C from 1 January 2000 to 31 December 2016, with follow-up to 30 June 2018. We estimated the number still living with hepatitis C, adjusting for spontaneous clearance and mortality. RESULTS: The cohort comprised 45 391 people positive for hepatitis C. Of these, 13 346 (29%) received treatment and an estimated 28% (95% confidence interval (CI): 26-30%) were still living with chronic infection at 30 June 2018, with the remainder still living following spontaneous clearance (30%, 95% CI: 29-32%) or having died (12%, 95% CI: 12-12%). Half (50%) of those still living with hepatitis C were born from 1965 to 1980, and 74% first tested positive before 2011. CONCLUSIONS: Despite an enabling policy environment and subsidised therapy, many people in this cohort were not treated. Increased measures may be needed to engage people in care, including those who acquired hepatitis C more than 10 years ago.
Subject(s)
Hepatitis C , Humans , Female , Male , Middle Aged , Victoria/epidemiology , Adult , Aged , Cohort Studies , Hepatitis C/epidemiology , Hepatitis C/therapy , Hepatitis C/drug therapy , Longitudinal Studies , Registries , Young Adult , Information Storage and Retrieval , Antiviral Agents/therapeutic use , Adolescent , Hepatitis C, Chronic/epidemiology , Hepatitis C, Chronic/drug therapy , Health Services AccessibilityABSTRACT
OBJECTIVES: To assess associations between SARS-CoV-2 infection and the incidence of hospitalisation with selected respiratory and non-respiratory conditions in a largely SARS-CoV-2 vaccine-naïve population . DESIGN, SETTING, PARTICIPANTS: Self-control case series; analysis of population-wide surveillance and administrative data for all laboratory-confirmed COVID-19 cases notified to the Victorian Department of Health (onset, 23 January 2020 - 31 May 2021; ie, prior to widespread vaccination rollout) and linked hospital admissions data (admission dates to 30 September 2021). MAIN OUTCOME MEASURES: Hospitalisation of people with acute COVID-19; incidence rate ratios (IRRs) comparing incidence of hospitalisations with defined conditions (including cardiac, cerebrovascular, venous thrombo-embolic, coagulative, and renal disorders) from three days before to within 89 days of onset of COVID-19 with incidence during baseline period (60-365 days prior to COVID-19 onset). RESULTS: A total of 20 594 COVID-19 cases were notified; 2992 people (14.5%) were hospitalised with COVID-19. The incidence of hospitalisation within 89 days of onset of COVID-19 was higher than during the baseline period for several conditions, including myocarditis and pericarditis (IRR, 14.8; 95% CI, 3.2-68.3), thrombocytopenia (IRR, 7.4; 95% CI, 4.4-12.5), pulmonary embolism (IRR, 6.4; 95% CI, 3.6-11.4), acute myocardial infarction (IRR, 3.9; 95% CI, 2.6-5.8), and cerebral infarction (IRR, 2.3; 95% CI, 1.4-3.9). CONCLUSION: SARS-CoV-2 infection is associated with higher incidence of hospitalisation with several respiratory and non-respiratory conditions. Our findings reinforce the value of COVID-19 mitigation measures such as vaccination, and awareness of these associations should assist the clinical management of people with histories of SARS-CoV-2 infection.
Subject(s)
COVID-19 , Myocardial Infarction , Humans , COVID-19/epidemiology , COVID-19 Vaccines , SARS-CoV-2 , HospitalizationABSTRACT
BACKGROUND AND AIM: This study aimed to assess utilization of health-care services in people with decompensated cirrhosis (DC) or hepatocellular carcinoma (HCC) and a "late diagnosis" of hepatitis B or hepatitis C. METHODS: Hepatitis B and C cases during 1997-2016 in Victoria, Australia, were linked with hospitalizations, deaths, liver cancer diagnoses, and medical services. A late diagnosis was defined as hepatitis B or hepatitis C notification occurring after, at the same time, or within 2 years preceding an HCC/DC diagnosis. Services provided during the 10-year period before HCC/DC diagnosis were assessed, including general practitioner (GP) or specialist visits, emergency department presentations, hospital admissions, and blood tests. RESULTS: Of the 25 766 notified cases of hepatitis B, 751 (2.9%) were diagnosed with HCC/DC, and hepatitis B was diagnosed late in 385 (51.3%). Of 44 317 cases of hepatitis C, 2576 (5.8%) were diagnosed with HCC/DC, and hepatitis C was diagnosed late in 857 (33.3%). Although late diagnosis dropped over time, missed opportunities for timely diagnosis were observed. Most people diagnosed late had visited a GP (97.4% for hepatitis B, 98.9% for hepatitis C) or had a blood test (90.9% for hepatitis B, 88.6% for hepatitis C) during the 10 years before HCC/DC diagnosis. The median number of GP visits was 24 and 32, and blood tests 7 and 8, for hepatitis B and C, respectively. CONCLUSIONS: Late diagnosis of viral hepatitis remains a concern, with the majority having frequent health-care service provision in the preceding period, indicating missed opportunities for diagnosis.
Subject(s)
Carcinoma, Hepatocellular , Hepatitis B , Hepatitis C , Liver Neoplasms , Humans , Carcinoma, Hepatocellular/diagnosis , Carcinoma, Hepatocellular/etiology , Carcinoma, Hepatocellular/pathology , Liver Neoplasms/diagnosis , Liver Neoplasms/etiology , Liver Neoplasms/pathology , Hepatitis B/complications , Hepatitis B/diagnosis , Hepatitis C/complications , Hepatitis C/diagnosis , Hepatitis B virus , Hepacivirus , Liver Cirrhosis/diagnosisABSTRACT
OBJECTIVES: To assess variations by time of year and hospital in the uptake of influenza and pertussis vaccinations by pregnant women in Victoria; to identify factors associated with vaccination uptake. DESIGN, SETTING: Retrospective analysis of data in the Victorian Perinatal Data Collection (VPDC), a population surveillance system for obstetric conditions, procedures, and pregnancy and birth outcomes. PARTICIPANTS: Women whose pregnancies ended in a live or stillbirth during July 2015 - June 2017. MAIN OUTCOME MEASURES: Influenza and pertussis vaccinations during pregnancy. RESULTS: 153 980 pregnancies in 67 hospitals ended during July 2015 - June 2017; 59 968 pregnant women (39.0%) were vaccinated against influenza and 98 583 (64.0%) against pertussis. Coverage varied by pregnancy end date, rising for influenza during winter and spring, but for pertussis rising continuously across the two years from 37.5% to 82.2%. Differences between hospitals in coverage were marked. Factors associated with vaccination included greater maternal age, primigravidity, early antenatal care, and GP-led care. The odds of vaccination were statistically significantly lower for women born overseas and those who smoked during pregnancy; the odds of vaccination were also lower for Aboriginal and Torres Strait Islander women. CONCLUSIONS: Pertussis vaccination of pregnant women in Victoria has increased, but influenza vaccination rates remain moderate and variable. Structural changes at the system level may improve maternal vaccination rates. Embedding the delivery of maternal vaccination programs in antenatal care pathways should be a priority.
Subject(s)
Influenza, Human/prevention & control , Patient Acceptance of Health Care/statistics & numerical data , Pregnancy Complications, Infectious/prevention & control , Vaccination/statistics & numerical data , Whooping Cough/prevention & control , Adult , Female , Humans , Influenza, Human/epidemiology , Pregnancy , Pregnancy Complications, Infectious/epidemiology , Prenatal Care/methods , Victoria , Whooping Cough/epidemiology , Young AdultSubject(s)
Influenza, Human , Whooping Cough , Female , Humans , Pregnancy , Vaccination , Vaccination CoverageABSTRACT
BACKGROUND: The Coronavirus Disease 2019 (COVID-19) pandemic led to extensive vaccination campaigns worldwide, including in Australia. Immunity waning and the emergence of new viral variants pose challenges to the effectiveness of vaccines. Our study aimed to assess the relative effectiveness (rVE) of 3 and 4 compared with 2 doses of COVID-19 vaccine. The study focuses on the Victorian population, a majority of whom had no prior exposure to the virus before vaccination. METHODS: We used routinely collected data for the state of Victoria, Australia, to assess rVE during an Omicron-dominant period, 1 June 2022 to 1 March 2023. Immunisation, notifications, hospitalisations and mortality data for residents aged 65 years and older were linked for analysis. Cox proportional hazard regression was used to estimate the rVE against COVID-19 hospitalisation or death, accounting for key confounders with vaccination as a time-varying covariate. RESULTS: In 1,070,113 people 65 years or older who had received their second dose, a third and fourth dose of a COVID-19 vaccine significantly reduced the hazard of hospitalisation or death compared to two doses. rVE was highest within two weeks from administration at 40 % (95 % CI: 0 % to 64 %) and 66 % (95 % CI: 60 % to 71 %) for a third and fourth dose, respectively. Additional protection conferred by third and fourth doses waned over time from administration. CONCLUSIONS: Our findings underscore the need for additional vaccine doses and updated vaccine strategies. These findings have implications for public health advice and COVID-19 vaccine strategies. Further research and monitoring of vaccine effectiveness in real-world settings are warranted to inform ongoing pandemic response efforts.
Subject(s)
COVID-19 Vaccines , COVID-19 , Humans , Victoria/epidemiology , COVID-19/prevention & control , Vaccination , ImmunizationABSTRACT
Objectives: To compare serological evidence of prior severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with linked coronavirus disease 2019 (COVID-19) case notification data in Victoria, Australia, and to determine in vitro SARS-CoV-2 neutralisation activity based on prior infection and vaccination history. Design, setting, participants: Four cross-sectional serological surveys were conducted between 30 June and 31 October 2022 (a period of Omicron BA.4/BA.5 dominance) using 1,974 residual serum samples obtained from the Victorian Infectious Diseases Reference Laboratory. Serological results were linked to COVID-19 case notification and vaccination data. Surrogate virus neutralisation testing was performed to obtain in vitro inhibition estimates by anti-nucleocapsid serostatus and COVID-19 vaccination history. Main outcome measures: Adjusted anti-SARS-CoV-2 spike and nucleocapsid seropositivity by sex, age and region of residence; adjusted proportion of cases notified by anti-nucleocapsid serostatus, age and number of COVID-19 vaccination doses received; adjusted percentage in vitro inhibition against wildtype and Omicron BA.4/BA.5 SARS-CoV-2 variants by anti-nucleocapsid serostatus and COVID-19 vaccination history. Results: The prevalence of anti-SARS-CoV-2 nucleocapsid antibodies was inversely proportional to age. In October 2022, prevalence was 84% (95% confidence interval [95% CI]: 75-93%) among 18-29-year-olds, compared to 39% (95% CI: 27-52%) among ≥ 80-year-olds. In most age groups, approximately 40% of COVID-19 cases appear to have been notified via existing surveillance mechanisms. Case notification was highest among individuals older than 80 years and people who had received COVID-19 vaccine booster doses. In vitro neutralisation of Omicron BA.4/BA.5 sub-variants was highest for individuals with evidence of both prior infection and booster vaccination. Conclusions: Under-notification of SARS-CoV-2 infections in the Victorian population is not uniform across age and vaccination strata. Seroprevalence data that give insights into case notification behaviour provide additional context for the interpretation of existing COVID-19 surveillance information.
Subject(s)
Antibodies, Viral , COVID-19 Vaccines , COVID-19 , SARS-CoV-2 , Vaccination , Humans , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19/immunology , Male , Female , Victoria/epidemiology , Middle Aged , Adult , SARS-CoV-2/immunology , Aged , Adolescent , Young Adult , Antibodies, Viral/blood , COVID-19 Vaccines/immunology , COVID-19 Vaccines/administration & dosage , Cross-Sectional Studies , Seroepidemiologic Studies , Aged, 80 and over , Child , Child, Preschool , Age Factors , Infant , Antibodies, Neutralizing/bloodABSTRACT
BACKGROUND: The Victorian Government Department of Health funded a diphtheria, tetanus and acellular pertussis vaccine for parents of infants from June 2009 to June 2012 as part of a cocooning strategy for the control of pertussis. The aim of this study was to assess parents' attitudes and awareness of the vaccination program, and to estimate vaccine uptake. METHODS: A cross-sectional survey of 253 families with a child born in the first quarter of 2010 residing within five metropolitan and four rural local government areas in Victoria was conducted. Univariate analyses were performed to describe the relationship between demographic variables, knowledge and awareness of the disease, the vaccine program and vaccine uptake. Multivariate analyses examining predictors for awareness of the vaccine program and for the uptake of vaccination were also conducted. RESULTS: One hundred and five families were surveyed (response rate 43%). Of these, 93% indicated that they had heard of 'pertussis' or 'whooping cough' and 75% of mothers and 69% of fathers were aware the pertussis vaccine was available and funded for new parents. Overall, 70% of mothers and 53% of fathers were vaccinated following their child's birth, with metropolitan fathers less likely to be vaccinated as rural fathers (RR=0.6, p=0.002). Being a younger mother (p=0.02) or father (p=0.047), and being an Australian-born father (RR=1.9, p=0.03) were found to predict uptake of the vaccine in parents. CONCLUSION: Parents indicated a reasonable level of knowledge of pertussis and a willingness to be vaccinated to protect their child. However, vaccine uptake estimates indicated further opportunity for program improvement. Future cocooning strategies would benefit from specifically targeting fathers and metropolitan maternity hospitals to increase vaccine uptake. Wider promotion of the availability of vaccine providers may increase uptake to maximise the success of cocooning programs. Further investigation of the effectiveness of the cocooning strategy in decreasing infant morbidity and mortality is required.
Subject(s)
Health Knowledge, Attitudes, Practice , Immunization, Secondary/statistics & numerical data , Parents/psychology , Pertussis Vaccine/administration & dosage , Whooping Cough/psychology , Adult , Cross-Sectional Studies , Female , Health Promotion/methods , Humans , Immunization Schedule , Male , Middle Aged , Multivariate Analysis , Rural Population , Social Class , Surveys and Questionnaires , Victoria , Whooping Cough/prevention & control , Young AdultABSTRACT
BACKGROUND: Mother-to-child transmission (MTCT) of hepatitis B virus (HBV) remains one of the leading causes of transmission worldwide. An estimated 90 % of infants who are exposed to HBV and do not receive appropriate post exposure immunoprophylaxis will go on to develop chronic hepatitis B (CHB). In Australia, universal birth dose vaccination was adopted in 2000 and universal antenatal screening for hepatitis B was introduced in the 1990 s, however up to 10 % of women may have missed screening. There is no coordinated care or data collection that systematically reports the access to interventions to prevent mother-to-child transmission (PMTCT) for women with CHB. Therefore, the incidence rate of MTCT is unknown. METHODS: We conducted retrospective data linkage of perinatal records, public health notification and hospital admission data to identify women with a record of HBV infection who had given birth to a live infant(s) in Victoria between 2009 and 2017. We assessed uptake of birth dose vaccination and hepatitis B immunoglobulin (HBIG) and explored factors associated with administration of birth dose recorded as administered within 7 days. RESULTS: Among 690,052 live births, 6118 births (0.90 %) were linked to 4196 women with a record of HBV infection. 89.4 % of all Victorian infants (n = 616,879), and 96.8 % of infants linked to women with a positive record of CHB (n = 5,925) received birth dose within 7 days. Infants born in private hospitals had reduced odds of receiving birth dose when compared to public hospitals births (Victorian population, aOR = 0.67, 95 %CI = 0.66, 0.69; CHB linked records aOR = 0.17, 95 %CI = 0.11, 0.25). Of the 6118 infants linked to a positive maternal record of CHB, discrepant recording of maternal CHB status between the three datasets was identified in 72.4% of records and HBIG administration was recorded for only 2.3% of births. CONCLUSION: An approach that involves coordinated care and integrates data collection for women with CHB and their infants is required to support the elimination of MTCT of hepatitis B in Victoria.
Subject(s)
Hepatitis B , Pregnancy Complications, Infectious , Humans , Female , Infant , Pregnancy , Victoria , Retrospective Studies , Infectious Disease Transmission, Vertical/prevention & control , Hepatitis B/prevention & control , Hepatitis B virus , Hepatitis B Surface Antigens , Pregnancy Complications, Infectious/epidemiology , Hepatitis B VaccinesABSTRACT
Background: Understanding mortality burden associated with communicable diseases is key to informing resource allocation, disease prevention and control efforts, and evaluating public health interventions. We quantified excess mortality among people notified with communicable diseases in Victoria, Australia. Methods: Cases of communicable disease notified in Victoria between 1 January 1991 and 31 December 2021 were linked to the death registry. Informational gain obtained through linkage and 30-day case fatality rates were calculated for each disease. Standardised mortality ratios (SMR) and 95% confidence intervals were calculated up to a year following illness onset. Findings: There were 1,032,619 cases and 5985 (0.58%) died ≤30 days of illness onset. Following linkage, the 30-day case fatality rate increased more than 2-fold. Diseases with high 7-day SMR signifying excess mortality included invasive pneumococcal disease (167.7, 95% CI 153.4-182.7); listeriosis (166.2, 95% CI 121.2-218.3); invasive meningococcal disease (145.9, 95% CI 116.7-178.3); legionellosis (43.3, 95% CI 28.0-62.0); and COVID-19 (21.9, 95% CI 19.7-24.3). Most diseases exhibited a strong negative gradient, with high SMRs in the first 7-days of illness onset that reduced over time. Interpretation: We demonstrated that the rate of death in Victoria's notifiable disease surveillance dataset is underestimated. Further, compared to a general population, there is evidence of elevated all-cause mortality among people notified with communicable diseases often up to one year following illness onset. Not all elevated risk is likely directly attributable to the communicable diseases of interest, rather, it may reflect underlying comorbidities or behaviours in these individuals. Regardless of attribution, infection with communicable diseases may represent a marker of mortality. Key to preventing deaths may be through timely and appropriate transition to primary and preventive healthcare following diagnosis. Funding: No funding was provided for this study.
ABSTRACT
BACKGROUND: Standard care for pregnant women includes universal screening for hepatitis B, and administration of influenza and pertussis vaccination to women and hepatitis B infant vaccination. This study explored how perinatal services relating to the prevention of these vaccine-preventable diseases are delivered to women and their infants in Victoria, Australia. METHODS: Two online surveys investigated service delivery for the prevention of influenza, pertussis and hepatitis B to identify barriers to optimal care during January-June 2021; (1) The Birthing Hospitals Survey captured facility-level information about service delivery for influenza and pertussis vaccination, and interventions to prevent mother-to-child-transmission of chronic hepatitis B (CHB); and (2) The Healthcare Providers Survey captured individual staff perceptions and knowledge in community and hospital settings. RESULTS: Thirty-four hospital unit managers (61%) completed The Birthing Hospitals Survey . One-hundred and forty participants completed The Healthcare Providers Survey . Half of the birthing hospitals provided influenza (50%) and pertussis (53%) vaccinations to pregnant women, and 53% provided an infectious diseases service for women with CHB. Barriers to optimal care delivery included reliance on pregnant woman's self-report to confirm influenza, pertussis vaccination and CHB status, lack of standardised reporting, inadequate workforce training, poor communication between services, and lack of guideline-based clinical care for mothers with CHB and their infants. Three hospitals reported 'stock out' of hepatitis B immunoglobulin (HBIG). CONCLUSION: Coordinated and standardised system and clinical care improvements are required to provide equitable care for pregnant women and their infants, including training and education for healthcare providers, improving data capture and communication among health services.
Subject(s)
Hepatitis B , Influenza Vaccines , Influenza, Human , Whooping Cough , Infant , Female , Pregnancy , Humans , Influenza, Human/prevention & control , Whooping Cough/prevention & control , Victoria , Infectious Disease Transmission, Vertical/prevention & control , VaccinationABSTRACT
BACKGROUND: A large outbreak of hepatitis A affected individuals in several Australian states in 2009, resulting in a 2-fold increase in cases reported to state health departments compared with 2008. Two peaks of infection occurred (April-May and September-November), with surveillance data suggesting locally acquired infections from a widely distributed food product. METHODS: Two case-control studies were completed. Intensive product trace-back and food sampling was undertaken. Genotyping was conducted on virus isolates from patient serum and food samples. Control measures included prophylaxis for close contacts, public health warnings, an order by the chief health officer under the Victorian Food Act 1984, and trade-level recalls on implicated batches of semidried tomatoes. RESULTS: A multijurisdictional case-control study in April-May found an association between illness and consumption of semidried tomatoes (odds ratio [OR], 3.0; 95% CI 1.4-6.7). A second case-control study conducted in Victoria in October-November also implicated semidried tomatoes as being associated with illness (OR, 10.3; 95% CI, 4.7-22.7). Hepatitis A RNA was detected in 22 samples of semidried tomatoes. Hepatitis A virus genotype IB was identified in 144 of 153 (94%) patients tested from 2009, and partial sequence analysis showed complete identity with an isolate found in a sample of semidried tomatoes. CONCLUSIONS: The results of both case-control studies and food testing implicated the novel vehicle of semidried tomatoes as the cause of this hepatitis A outbreak. The outbreak was extensive and sustained despite public health interventions, the design and implementation of which were complicated by limitations in food testing capability and complex supply chains.
Subject(s)
Disease Outbreaks , Hepatitis A Virus, Human/isolation & purification , Hepatitis A/epidemiology , RNA, Viral/isolation & purification , Solanum lycopersicum/virology , Adolescent , Adult , Australia/epidemiology , Case-Control Studies , Female , Food Microbiology , Food, Preserved/virology , Genotype , Hepatitis A/virology , Hepatitis A Virus, Human/genetics , Humans , Male , Middle Aged , Product Recalls and Withdrawals , Young AdultABSTRACT
BACKGROUND: Interest in the use of emergency department (ED) data by syndromic surveillance systems to detect influenza outbreaks has been growing. Evaluations of these systems generally focus on events during influenza seasons. The aims of this study were to identify which emergency department disease codes best correlated with confirmed influenza cases and to determine if these same codes would be useful in the non-influenza season. The 2009 influenza pandemic in Victoria, Australia, provided further opportunity to examine the performance of the syndromic surveillance system during this event. METHODS: We undertook a retrospective analysis of data from the Victorian Department of Health's pilot syndromic surveillance programme, 'SynSurv'. SynSurv automatically captures patient information as it is entered by ED staff. This information includes patient demographics, their presenting symptoms and a preliminary diagnosis using ICD-10 coding. To determine which codes were best correlated with influenza notifications, weekly counts for each of the ICD-10 diagnosis codes ever used in the dataset were calculated and compared with the corresponding weekly count of confirmed influenza cases. Correlations between these codes and confirmed influenza cases in the non-influenza season were then undertaken. The data covered the period from July 2001 until August 2009 and included the 2009 influenza pandemic. RESULTS: There was a marked increase in weekly counts of both laboratory-confirmed influenza cases and relevant ICD-10 codes during the influenza pandemic period. The increase in laboratory confirmed cases was more than four times greater than the previous highest number reported, in 2007, even though the influenza-like-illness activity in the community was considered comparable to 2003 and 2007. We found five ICD-10 codes to be moderately and significantly correlated with influenza cases. None of these codes was correlated with laboratory confirmed influenza notifications outside the influenza season, at least in part because of the small number of influenza cases notified during that period. CONCLUSIONS: This study suggests that the choice of codes made by ED staff to record a case of influenza-like illness is influenced by their perceptions of how much influenza is circulating at the time. The ability of syndromic surveillance to detect outbreaks early may be impeded because case diagnosis is influenced by what ED staff believes to be occurring in the community.
Subject(s)
Disease Notification , Emergency Service, Hospital , Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza, Human/diagnosis , International Classification of Diseases , Population Surveillance/methods , Humans , Influenza, Human/epidemiology , Pandemics , Retrospective Studies , Victoria/epidemiologyABSTRACT
BACKGROUND AND OBJECTIVES: Infant influenza and pertussis disease causes considerable morbidity and mortality worldwide. We examined the effectiveness of maternal influenza and pertussis vaccines in preventing these diseases in infants. METHODS: This inception cohort study comprised women whose pregnancies ended between September 1, 2015, and December 31, 2017, in Victoria, Australia. Maternal vaccination status was sourced from the Victorian Perinatal Data Collection and linked to 5 data sets to ascertain infant outcomes and vaccination. The primary outcome of interest was laboratory-confirmed influenza or pertussis disease in infants aged <2 months, 2 to <6 months, and <6 months combined. Secondary outcomes included infant hospitalization (emergency presentation or admission) and death. Risk ratios and 95% confidence intervals (CIs) were estimated by Poisson regression. Vaccine effectiveness (VE) was estimated as (1 minus the risk ratio) x 100%. RESULTS: Among 186 962 pregnant women, 85 830 (45.9%) and 128 060 (68.5%) were vaccinated against influenza and pertussis, respectively. There were 175 and 51 infants with laboratory-confirmed influenza and pertussis disease, respectively. Influenza VE was 56.1% (95% CI, 23.3% to 74.9%) for infants aged <2 months and 35.7% (2.2% to 57.7%) for infants aged 2 to <6 months. Pertussis VE was 80.1% (95% CI, 37.1% to 93.7%) for infants aged <2 months and 31.8% (95% CI, -39.1% to 66.6%) for infants aged 2 to <6 months. CONCLUSIONS: Our study provides evidence of the direct effectiveness of maternal influenza and pertussis vaccination in preventing these diseases in infants aged <2 months. The findings strengthen the importance of maternal vaccination to prevent these diseases in infants.
Subject(s)
Influenza, Human/prevention & control , Pertussis Vaccine/immunology , Adult , Cohort Studies , Diphtheria-Tetanus-acellular Pertussis Vaccines , Female , Humans , Infant , Infant, Newborn , Influenza Vaccines , Parturition , Pregnancy , Pregnancy Complications, Infectious/prevention & control , Pregnant Women , Vaccination/statistics & numerical data , Victoria , Whooping Cough/prevention & controlABSTRACT
BACKGROUND: Infectious diseases are a leading cause of hospitalization during childhood. The various mitigation strategies implemented to control the coronavirus disease (COVID-19) pandemic could have additional, unintended benefits for limiting the spread of other infectious diseases and their associated burden on the health care system. METHODS: We conducted an interrupted time-series analysis using population-wide hospitalization data for the state of Victoria, Australia. Infection-related hospitalizations for children and adolescents (aged <18 years, total source population â¼1.4 million) were extracted using pre-defined International Classification of Diseases 10th Revision Australian Modification (ICD-10-AM) codes. The change in weekly hospitalization rates (incidence rate ratio, IRR) for all infections following the introduction of pandemic-related restrictions from 15 March 2020 was estimated. RESULTS: Over 2015-19, the mean annual incidence of hospitalization with infection among children less than 18 years was 37 per 1000 population. There was an estimated 65% (95% CI 62-67%) reduction in the incidence of overall infection-related hospitalizations associated with the introduction of pandemic restrictions. The reduction was most marked in younger children (at least 66% in those less than 5 years of age) and for lower respiratory tract infections (relative reduction 85%, 95% CI 85-86%). CONCLUSIONS: The wider impacts of pandemic mitigation strategies on non-COVID-19 infection-related hospitalizations are poorly understood. We observed marked and rapid decreases in hospitalized childhood infection. In tandem with broader consequences, sustainable measures, such as improved hand hygiene, could reduce the burden of severe childhood infection post-pandemic and the social and economic costs of hospitalization.
Subject(s)
COVID-19 , Pandemics , Adolescent , Child , Hospitalization , Humans , Pandemics/prevention & control , SARS-CoV-2 , Victoria/epidemiologyABSTRACT
BACKGROUND: Public health surveillance is crucial for supporting a rapid and effective response to public health emergencies. In response to the coronavirus disease (COVID-19) pandemic, an enhanced surveillance system of hospitalised COVID-19 patients was established by the Victorian Department of Health and Human Services (DHHS) and the Victorian Healthcare Associated Infection Surveillance System Coordinating Centre. The system aimed to reduce workforce capacity constraints and increase situational awareness on the status of hospitalised patients. METHODS: The system was evaluated, using guidelines from the United States Centers for Disease Control and Prevention, against eight attributes: acceptability; data quality; flexibility; representativeness; simplicity; stability; timeliness; and usefulness. Evidence was generated from stakeholder consultation, participant observation, document review, systems review, issues log review and audits. Data were collected and analysed over a period of up to three months, covering pre- and post-implementation from March to June 2020. RESULTS: This system was rapidly established by leveraging established relationships and infrastructure. Stakeholders agreed that the system was important but was limited by a reliance on daily manual labour (including weekends), which impeded scalability. The ability of the system to perform well in each attribute was expected to shift with the severity of the pandemic; however, at the time of this evaluation, when there were an average 23 new cases per day (0.3 cases per 100,000 population per day), the system performed well. CONCLUSION: This enhanced surveillance system was useful and achieved its key DHHS objectives during the COVID-19 public health emergency in Victoria. Recommendations for improvement were made to the current and future systems, including the need to plan alternatives to improve the system's scalability and to maintain stakeholder acceptability.
Subject(s)
COVID-19/epidemiology , Hospitalization/statistics & numerical data , Population Surveillance/methods , Public Health/methods , COVID-19/diagnosis , Data Accuracy , Humans , Program Evaluation , Public Health/standards , Public Health Administration , SARS-CoV-2 , Stakeholder Participation , Time Factors , Victoria/epidemiologyABSTRACT
OBJECTIVES: To review the use of data linkage by Australian state and territory communicable disease control units, and to identify barriers to and enablers of data linkage to inform communicable disease surveillance and control activities. METHODS: Semi-structured telephone interviews were carried out with one key informant from communicable disease control units in all eight Australian states and territories between October 2017 and January 2018. RESULTS: Key informants from all Australian states and territories participated in the interview. A variety of existing practices were identified, with few jurisdictions making systematic use of available data linkage infrastructure. Key barriers identified from the review included: a lack of perceived need; system factors; and resources. Existing regulatory tools enable data linkage to enhance communicable disease surveillance and control. CONCLUSIONS: We identified considerable variation in the use of data linkage to inform communicable disease surveillance and control activities between jurisdictions. We suggest that routinely collected, disparate data are systematically integrated into existing surveillance and response policy cycle to improve communicable disease prevention and control efforts. Implications for public health: Existing gaps in communicable disease surveillance data may affect prevention and control efforts. Data linkage is recognised as a valuable method to close surveillance gaps and should be used to enhance the value of publicly held health data.