Influenza Vaccine Effectiveness Against Influenza-Related Mortality in Australian Hospitalized Patients: A Propensity Score Analysis.

BACKGROUND: Data on influenza vaccine effectiveness (IVE) against mortality are limited, with no Australian data to guide vaccine uptake. We aimed to assess IVE against influenza-related mortality in Australian hospitalized patients, assess residual confounding in the association between influenza vaccination and mortality, and assess whether influenza vaccination reduces the severity of influenza illness. METHODS: Data were collected between 2010 and 2017 from a national Australian hospital-based sentinel surveillance system using a case-control design. Adults and children admitted to the 17 study hospitals with acute respiratory symptoms were tested for influenza using nucleic acid testing; all eligible test-positive cases, and a subset of test-negative controls, were included. Propensity score analysis and multivariable logistic regression were used to determine the adjusted odds ratio (aOR) of vaccination, with IVE = 1 - aOR × 100%. Residual confounding was assessed by examining mortality in controls. RESULTS: Over 8 seasons, 14038 patients were admitted with laboratory-confirmed influenza. The primary analysis included 9298 cases and 6451 controls, with 194 cases and 136 controls dying during hospitalization. Vaccination was associated with a 31% (95% confidence interval [CI], 3%-51%; P = .033) reduction in influenza-related mortality, with similar estimates in the National Immunisation Program target group. Residual confounding was identified in patients ≥65 years old (aOR, 1.92 [95% CI, 1.06-3.46]; P = .031). There was no evidence that vaccination reduced the severity of influenza illness (aOR, 1.07 [95% CI, .76-1.50]; P = .713). CONCLUSIONS: Influenza vaccination is associated with a moderate reduction in influenza-related mortality. This finding reinforces the utility of the Australian vaccination program in protecting those most at risk of influenza-related deaths.

Cardiac procedures in ST-segment-elevation myocardial infarction - the influence of age, geography and Aboriginality.

BACKGROUND: Timely restoration of bloodflow acute ST-segment elevation myocardial infarction (STEMI) reduces myocardial damage and improves prognosis. The objective of this study was describe the association of demographic factors with hospitalisation rates for STEMI and time to angiography, Percutaneous Coronary Intervention (PCI) and Coronary Artery Bypass Graft (CABG) in New South Wales (NSW) and the Australian Capital Territory (ACT), Australia. METHODS: This was an observational cohort study using linked population health data. We used linked records of NSW and the ACT hospitalisations and the Australian Government Medicare Benefits Schedule (MBS) for persons aged 35 and over hospitalised with STEMI in the period 1 July 2010 to 30 June 2014. Survival analysis was used to determine the time between STEMI admission and angiography, PCI and CABG, with a competing risk of death without cardiac procedure. RESULTS: Of 13,117 STEMI hospitalisations, 71% were among males; 55% were 65-plus years; 64% lived in major cities, and 2.6% were Aboriginal people. STEMI hospitalisation occurred at a younger age in males than females. Angiography and PCI rates decreased with age: angiography 69% vs 42% and PCI 60% vs 34% on day 0 for ages 35-44 and 75-plus respectively. Lower angiography and PCI rates and higher CABG rates were observed outside major cities. Aboriginal people with STEMI were younger and more likely to live outside a major city. Angiography, PCI and CABG rates were similar for Aboriginal and non-Aboriginal people of the same age and remoteness area. CONCLUSIONS: There is a need to improve access to definitive revascularisation for STEMI among appropriately selected older patients and in regional areas. Aboriginal people with STEMI, as a population, are disproportionately affected by access to definitive revascularisation outside major cities. Improving access to timely definitive revascularisation in regional areas may assist in closing the gap in cardiovascular outcomes between Aboriginal and non-Aboriginal people.

Influenza Epidemiology, Vaccine Coverage and Vaccine Effectiveness in Children Admitted to Sentinel Australian Hospitals in 2017: Results from the PAEDS-FluCAN Collaboration.

BACKGROUND: In 2017, Australia experienced record influenza notifications. Two surveillance programs combined to summarize the epidemiology of hospitalized influenza in children and report on vaccine effectiveness (VE) in the context of a limited nationally funded vaccination program. METHODS: Subjects were prospectively recruited (April-October 2017). Case patients were children aged ≤16 years admitted to 11 hospitals with an acute respiratory illness and laboratory-confirmed influenza. Controls were hospitalized with acute respiratory illness and tested negative for influenza. VE estimates were calculated using the test-negative design. RESULTS: A total of 1268 children were hospitalized with influenza: 31.5% were <2 years old, 8.3% were indigenous, and 45.1% had comorbid conditions predisposing to severe influenza. Influenza B was detected in 34.1% with influenza A/H1N1 and A/H3N2 detected in 47.2% and 52.8% of subtyped influenza A specimens. The median length of stay was 3 days (interquartile range, 1-5), 14.5% were admitted to the intensive care unit, and 15.9% received oseltamivir. Four in-hospital deaths occurred (0.3%): one was considered influenza associated. Only 17.1% of test-negative-controls were vaccinated. The VE of inactivated quadrivalent influenza vaccine for preventing hospitalized influenza was estimated at 30.3% (95% confidence interval, 2.6%-50.2%). CONCLUSIONS: Significant influenza-associated morbidity was observed in 2017 in Australia. Most hospitalized children had no comorbid conditions. Vaccine coverage and antiviral use was inadequate. Influenza vaccine was protective in 2017, yet VE was lower than previous seasons. Multiple Australian states have introduced funded preschool vaccination programs in 2018. Additional efforts to promote vaccination and monitor effectiveness are required.

Decision makers' experience of participatory dynamic simulation modelling: methods for public health policy.

BACKGROUND: Systems science methods such as dynamic simulation modelling are well suited to address questions about public health policy as they consider the complexity, context and dynamic nature of system-wide behaviours. Advances in technology have led to increased accessibility and interest in systems methods to address complex health policy issues. However, the involvement of policy decision makers in health-related simulation model development has been lacking. Where end-users have been included, there has been limited examination of their experience of the participatory modelling process and their views about the utility of the findings. This paper reports the experience of end-user decision makers, including senior public health policy makers and health service providers, who participated in three participatory simulation modelling for health policy case studies (alcohol related harm, childhood obesity prevention, diabetes in pregnancy), and their perceptions of the value and efficacy of this method in an applied health sector context. METHODS: Semi-structured interviews were conducted with end-user participants from three participatory simulation modelling case studies in Australian real-world policy settings. Interviewees were employees of government agencies with jurisdiction over policy and program decisions and were purposively selected to include perspectives at different stages of model development. RESULTS: The 'co-production' aspect of the participatory approach was highly valued. It was reported as an essential component of building understanding of the modelling process, and thus trust in the model and its outputs as a decision-support tool. The unique benefits of simulation modelling included its capacity to explore interactions of risk factors and combined interventions, and the impact of scaling up interventions. Participants also valued simulating new interventions prior to implementation in the real world, and the comprehensive mapping of evidence and its gaps to prioritise future research. The participatory aspect of simulation modelling was time and resource intensive and therefore most suited to high priority complex topics with contested options for intervening. CONCLUSION: These findings highlight the value of a participatory approach to dynamic simulation modelling to support its utility in applied health policy settings.

Repeated Vaccination Does Not Appear to Impact Upon Influenza Vaccine Effectiveness Against Hospitalization With Confirmed Influenza.

BACKGROUND.: Annual influenza vaccine is recommended for those at greatest risk of severe influenza infection. Recent reports of a negative impact of serial influenza vaccination on vaccine effectiveness (VE) raises concerns about the recommendation for annual influenza vaccines, particularly in persons at greatest risk. METHODS.: The Influenza Complications Alert Network (FluCAN) is an Australian hospital-based sentinel surveillance program. In this observational study, cases were defined as subjects aged >9 years admitted with influenza confirmed by polymerase chain reaction. Controls were subjects with acute respiratory illness testing negative for influenza. Propensity scores were used to adjust for the likelihood of being vaccinated. VE was calculated as 1 - adjusted odds ratio of vaccination in cases compared with test-negative controls. RESULTS.: Over 2010-2015, 6223 cases and 6505 controls were hospitalized with confirmed influenza and influenza test-negative acute respiratory illness, respectively. Following stratification by quintile of propensity score, site, and year, VE was estimated to be 43% (95% confidence interval [CI], 37%-49%) overall. VE was estimated to be 51% (95% CI, 45%-57%) in those vaccinated in both the current and previous season, compared with 33% (95% CI, 17%-47%) vaccinated in the current season only and 35% (95% CI, 21%-46%) in the previous season only. Similar results were observed for influenza A/H1N1, influenza A/H3N2, and influenza B strains. CONCLUSIONS.: Vaccination in both the current and previous seasons was associated with a higher VE against hospitalization with influenza than vaccination in either single season. These findings reinforce current recommendations for annual influenza vaccination, particularly those at greatest risk of influenza disease.

Influenza epidemiology in patients admitted to sentinel Australian hospitals in 2015: the Influenza Complications Alert Network.

The Influenza Complications Alert Network (FluCAN) is a sentinel hospital-based surveillance program that operates at sites in all states and territories in Australia. This report summarises the epidemiology of hospitalisations with laboratory-confirmed influenza during the 2015 influenza season. In this observational study, cases were defined as patients admitted to one of the sentinel hospitals with an acute respiratory illness with influenza confirmed by nucleic acid detection. During the period 1 April to 30 October 2015 (the 2015 influenza season), 2,070 patients were admitted with confirmed influenza to one of 17 FluCAN sentinel hospitals. Of these, 46% were elderly (≥ 65 years), 15% were children (< 16 years), 5% were Indigenous Australians, 2.1% were pregnant and 75% had chronic co-morbidities. A high proportion were due to influenza B (51%). There were a large number of hospital admissions detected with confirmed influenza in this national observational surveillance system in 2015 with case numbers similar to that reported in 2014. The national immunisation program is estimated to avert 46% of admissions from confirmed influenza across all at-risk groups, but more complete vaccination coverage in target groups could further reduce influenza admissions by as much as 14%.

Development of the zebrafish mesonephros.

The vertebrate kidney plays an essential role in removing metabolic waste and balancing water and salt. This is carried out by nephrons, which comprise a blood filter attached to an epithelial tubule with proximal and distal segments. In zebrafish, two nephrons are first formed as part of the embryonic kidney (pronephros) and hundreds are formed later to make up the adult kidney (mesonephros). Previous studies have focused on the development of the pronephros while considerably less is known about how the mesonephros is formed. Here, we characterize mesonephros development in zebrafish and examine the nephrons that form during larval metamorphosis. These nephrons, arising from proliferating progenitor cells that express the renal transcription factor genes wt1b, pax2a, and lhx1a, form on top of the pronephric tubules and develop a segmentation pattern similar to pronephric nephrons. We find that the pronephros acts as a scaffold for the mesonephros, where new nephrons fuse with the distal segments of the pronephric tubules to form the final branching network that characterizes the adult zebrafish kidney.

Influenza epidemiology, vaccine coverage and vaccine effectiveness in sentinel Australian hospitals in 2013: the Influenza Complications Alert Network.

The National Influenza Program aims to reduce serious morbidity and mortality from influenza by providing public funding for vaccination to at-risk groups. The Influenza Complications Alert Network (FluCAN) is a sentinel hospital-based surveillance program that operates at 14 sites in all states and territories in Australia. This report summarises the epidemiology of hospitalisations with confirmed influenza, estimates vaccine coverage and influenza vaccine protection against hospitalisation with influenza during the 2013 influenza season. In this observational study, cases were defined as patients admitted to one of the sentinel hospitals, with influenza confirmed by nucleic acid testing. Controls were patients who had acute respiratory illnesses who were test-negative for influenza. Vaccine effectiveness was estimated as 1 minus the odds ratio of vaccination in case patients compared with control patients, after adjusting for known confounders. During the period 5 April to 31 October 2012, 631 patients were admitted with confirmed influenza at the 14 FluCAN sentinel hospitals. Of these, 31% were more than 65 years of age, 9.5% were Indigenous Australians, 4.3% were pregnant and 77% had chronic co-morbidities. Influenza B was detected in 30% of patients. Vaccination coverage was estimated at 81% in patients more than 65 years of age but only 49% in patients aged less than 65 years with chronic comorbidities. Vaccination effectiveness against hospitalisation with influenza was estimated at 50% (95% confidence interval: 33%, 63%, P<0.001). We detected a significant number of hospital admissions with confirmed influenza in a national observational study. Vaccine coverage was incomplete in at-risk groups, particularly non-elderly patients with medical comorbidities. Our results suggest that the seasonal influenza vaccine was moderately protective against hospitalisation with influenza in the 2013 season.

Impaired pulmonary nitric oxide bioavailability in pulmonary tuberculosis: association with disease severity and delayed mycobacterial clearance with treatment.

BACKGROUND: Nitric oxide (NO), a key macrophage antimycobacterial mediator that ameliorates immunopathology, is measurable in exhaled breath in individuals with pulmonary tuberculosis. We investigated relationships between fractional exhale NO (FENO) and initial pulmonary tuberculosis severity, change during treatment, and relationship with conversion of sputum culture to negative at 2 months. METHODS: In Papua, we measured FENO in patients with pulmonary tuberculosis at baseline and serially over 6 months and once in healthy controls. Treatment outcomes were conversion of sputum culture results at 2 months and time to conversion of sputum microscopy results. RESULTS: Among 200 patients with pulmonary tuberculosis and 88 controls, FENO was lower for patients with pulmonary tuberculosis at diagnosis (geometric mean FENO, 12.7 parts per billion [ppb]; 95% confidence interval [CI], 11.6-13.8) than for controls (geometric mean FENO, 16.6 ppb; 95% CI, 14.2-19.5; P = .002), fell further after treatment initiation (nadir at 1 week), and then recovered by 6 months (P = .03). Lower FENO was associated with more-severe tuberculosis disease, with FENO directly proportional to weight (P < .001) and forced vital-capacity (P = .001) and inversely proportional to radiological score (P = .03). People whose FENO increased or remained unchanged by 2 months were 2.7-fold more likely to achieve conversion of sputum culture than those whose FENO decreased (odds ratio, 2.72; 95% CI, 1.05-7.12; P = .04). CONCLUSIONS: Among patients with pulmonary tuberculosis, impaired pulmonary NO bioavailability is associated with more-severe disease and delayed mycobacterial clearance. Measures to increase pulmonary NO warrant investigation as adjunctive tuberculosis treatments.

An evaluation of the global network of field epidemiology and laboratory training programmes: a resource for improving public health capacity and increasing the number of public health professionals worldwide.

BACKGROUND: Given that many infectious diseases spread rapidly, across borders and species, there is a growing worldwide need to increase the number of public health professionals skilled in controlling infectious epidemics. Needed also are more public health professionals skilled in non-communicable disease surveillance and interventions. As a result, we surveyed all 57 field epidemiology training programmes (FETPs) that are members of the Training Program in Epidemiology and Public Health Interventions Network (TEPHINET), to evaluate the progress of the FETPs, the only global applied epidemiology network, toward increasing public health capacity globally. METHODS: Data on the FETP programmes and the training they provide were abstracted from TEPHINET membership surveys and verified with FETP directors for all FETPs that were members of TEPHINET in 2012. Data on abstracts submitted to the recent TEPHINET Global Scientific Conference, on recent accomplishments by each FETP, and on quality improvement were also compiled to provide a worldwide view of the public health human resource capacity produced by these programmes. RESULTS: A total of 6980 public health professionals worldwide have graduated from an FETP or from the Center for Disease Control and Prevention's Epidemiology Intelligence Service (EIS). FETP residents and graduates participate in key public health prevention, control, and response activities. Each FETP has adapted its curriculum and objectives over time to align with its country's public health priorities. FETPs are well integrated into their national public health infrastructures, and they have many partners at the national, regional and global levels. CONCLUSION: FETPs are a competent and diverse source of highly skilled public health professionals who contribute significantly to public health's global human resource needs. This finding is evidenced by 1) the training curricula that were adapted over time to meet public health's human resource needs, 2) the FETPs' continued support from internal and external partners, 3) the increasing number of FETP residents and graduates and their increasing contribution to effective public health work, and 4) the increased quality improvement initiatives facilitated through the FETPs membership in one global network, TEPHINET.

Changing the malaria treatment protocol policy in Timor-Leste: an examination of context, process, and actors' involvement.

In 2007 Timor-Leste, a malaria endemic country, changed its Malaria Treatment Protocol for uncomplicated falciparum malaria from sulphadoxine-pyrimethamine to artemether-lumefantrine. The change in treatment policy was based on the rise in morbidity due to malaria and perception of increasing drug resistance. Despite a lack of nationally available evidence on drug resistance, the Ministry of Health decided to change the protocol. The policy process leading to this change was examined through a qualitative study on how the country developed its revised treatment protocol for malaria. This process involved many actors and was led by the Timor-Leste Ministry of Health and the WHO country office. This paper examines the challenges and opportunities identified during this period of treatment protocol change.

Application of a healthy food markets guide to two Indonesian markets to reduce transmission of "avian flu".

PROBLEM: The World Health Organization (WHO) developed a guideline with 10 control measures to reduce transmission of A(H5N1) avian influenza virus in markets in low-resource settings. The practical aspects of guide implementation have never been described. APPROACH: WHO's guideline was implemented in two Indonesian markets in the city of Makassar to try to reduce transmission of the A(H5N1) virus. The guideline was operationalized using a participatory approach to introduce a combination of infrastructural and behavioural changes. LOCAL SETTING: Avian influenza is endemic in birds in Makassar. Two of the city's 22 dilapidated, poorly-run bird markets were chosen for the study. Before the intervention, neither market was following any of WHO's 10 recommended control measures except for batch processing. RELEVANT CHANGES: Market stakeholders' knowledge about the avian influenza A(H5N1) virus improved after the interventions. WHO guideline recommendations for visual inspection, cleaning and poultry-holding practices, as well as infrastructural requirements for zoning and for water supply and utilities, began to conform to the WHO guideline. Low-maintenance solutions such as installation of wastewater treatment systems and economic incentives such as composting were well received and appropriate for the low-resource setting. LESSONS LEARNT: Combining infrastructural changes with behaviour change interventions was critical to guideline implementation. Despite initial resistance to behaviour change, the participatory approach involving monthly consultations and educational sessions facilitated the adoption of safe food-handling practices and sanitation. Market authorities assumed important leadership roles during the interventions and this helped shift attitudes towards regulation and market maintenance needs. This shift may enhance the sustainability of the interventions.

Did the first Global Fund grant (2003-2006) contribute to malaria control and health system strengthening in Timor-Leste?

BACKGROUND: In 2003, Timor-Leste successfully obtained its first Global Fund grant for a three-year programme for malaria control. The grant aimed to reduce malaria-related morbidity and mortality by 30 % by the end of the implementation. METHODS: A mixed-methods approach was used to assess the impact of the grant implementation. Fifty-eight in-depth interviews, eight group interviews, 16 focus group discussions, and on-site observations were used. Morbidity data reported to the Ministry of Health were also examined to assess trends. RESULTS: The National Malaria Programme with funding support from the Global Fund grant and other development partners contributed considerably to strengthening malaria control and the general health system. It also brought direct and indirect benefits to pregnant women and to the community at large. However, it failed to achieve the stated objective of reducing malaria morbidity and mortality by 30 %. The implementation was hampered by inadequate human resources, the rigidity of Global Fund rules, weak project management and coordination, and inadequate support from external stakeholders. CONCLUSION: Despite limitations, the grant was implemented until the agreed closing date. Considerable contributions to malaria control, health system, and the community have been made and the malaria programme was sustained.

Risk factors for cluster outbreaks of avian influenza A H5N1 infection, Indonesia.

BACKGROUND: By 30 July 2009, Indonesia had reported 139 outbreaks of avian influenza (AI) H5N1 infection in humans. Risk factors for case clustering remain largely unknown. This study assesses risk factors for cluster outbreaks and for secondary case infection. METHODS: The 113 sporadic and 26 cluster outbreaks were compared on household and individual level variables. Variables assessed include those never reported previously, including household size and genealogical relationships between cases and their contacts. RESULTS: Cluster outbreaks had larger households and more blood-related contacts, especially first-degree relatives, compared with sporadic case outbreaks. Risk factors for cluster outbreaks were the number of first-degree blood-relatives to the index case (adjusted odds ratio [aOR], 1.50; 95% confidence interval [CI]: 1.20-1.86) and index cases having direct exposure to sources of AI H5N1 virus (aOR, 3.20; 95% CI: 1.15-8.90). Risk factors for secondary case infection were being aged between 5 and 17 years (aOR, 8.32; 95% CI: 1.72-40.25), or 18 and 30 years (aOR, 6.04; 95% CI: 1.21-30.08), having direct exposure to sources of AI H5N1 virus (aOR, 3.48; 95% CI: 1.28-9.46), and being a first-degree relative to an index case (aOR, 11.0; 95% CI: 1.43-84.66). Siblings to index cases were 5 times more likely to become secondary cases (OR, 4.72; 95% CI: 1.67-13.35). CONCLUSIONS: The type of exposure and the genealogical relationship between index cases and their contacts impacts the risk of clustering. The study adds evidence that AI H5N1 infection is influenced by, and may even depend on, host genetic susceptibility.

Transmission of influenza on international flights, may 2009.

Understanding the dynamics of influenza transmission on international flights is necessary for prioritizing public health response to pandemic incursions. A retrospective cohort study to ascertain in-flight transmission of pandemic (H1N1) 2009 and influenza-like illness (ILI) was undertaken for 2 long-haul flights entering Australia during May 2009. Combined results, including survey responses from 319 (43%) of 738 passengers, showed that 13 (2%) had an ILI in flight and an ILI developed in 32 (5%) passengers during the first week post arrival. Passengers were at 3.6% increased risk of contracting pandemic (H1N1) 2009 if they sat in the same row as or within 2 rows of persons who were symptomatic preflight. A closer exposed zone (2 seats in front, 2 seats behind, and 2 seats either side) increased the risk for postflight disease to 7.7%. Efficiency of contact tracing without compromising the effectiveness of the public health intervention might be improved by limiting the exposed zone.

Comparability of different methods for estimating influenza infection rates over a single epidemic wave.

Estimation of influenza infection rates is important for determination of the extent of epidemic spread and for calculation of severity indicators. The authors compared estimated infection rates from paired and cross-sectional serologic surveys, rates of influenza like illness (ILI) obtained from sentinel general practitioners (GPs), and ILI samples that tested positive for influenza using data from similar periods collected during the 2009 H1N1 epidemic in Singapore. The authors performed sensitivity analyses to assess the robustness of estimates to input parameter uncertainties, and they determined sample sizes required for differing levels of precision. Estimates from paired seroconversion were 17% (95% Bayesian credible interval (BCI): 14, 20), higher than those from cross-sectional serology (12%, 95% BCI: 9, 17). Adjusted ILI estimates were 15% (95% BCI: 10, 25), and estimates computed from ILI and laboratory data were 12% (95% BCI: 8, 18). Serologic estimates were least sensitive to the risk of input parameter misspecification. ILI-based estimates were more sensitive to parameter misspecification, though this was lessened by incorporation of laboratory data. Obtaining a 5-percentage-point spread for the 95% confidence interval in infection rates would require more than 1,000 participants per serologic study, a sentinel network of 90 GPs, or 50 GPs when combined with laboratory samples. The various types of estimates will provide comparable findings if accurate input parameters can be obtained.

FluCAN 2009: initial results from sentinel surveillance for adult influenza and pneumonia in eight Australian hospitals.

OBJECTIVE: To describe the epidemiology of adult patients hospitalised with influenza or pneumonia during a pandemic season in a sentinel network in Australia. DESIGN, PARTICIPANTS AND SETTING: Prospective case series of adult hospital admissions to eight acute care general public hospitals (Influenza Complications Alert Network [Flu CAN] sentinel hospitals) in six Australian jurisdictions, 1 July to 4 December 2009. MAIN OUTCOME MEASURES: Demographic, clinical and outcome measures in patients admitted with laboratory-confirmed pandemic (H1N1) 2009 influenza in the sentinel hospitals compared with data from national notifications and intensive care unit (ICU) surveillance; admissions for influenza and pneumonia over time in each jurisdiction. RESULTS: During 190 hospital-weeks of observation, there were 538 influenza admissions. Of these, 465 patients (86.4%) had the pandemic strain, representing 9.3% of total admissions with pandemic (H1N1) 2009 influenza (n = 4992) recorded nationally in 2009. Of these patients, 250/465 (53.8%) were women, 67/453 (14.8%) were Indigenous, and the median age was 46 years (interquartile range, 29-58 years). Comorbidities were present in 354/464 patients (76.3%), and 40 were pregnant (30.3% of women aged 15-49 years). FluCAN reported that 102 patients (21.9%) were admitted to ICUs, and of patients admitted to hospital, 26 (5.6%) died. FluCAN results were very similar to national notification data and published ICU admissions data. Of those who were followed to 30 days after discharge, 30 (6.5%) were readmitted. Of 1468 patients hospitalised with pneumonia, 718 (48.9%) were tested for influenza and 163 (11.1%) were co-infected with the pandemic strain. CONCLUSIONS: Sentinel surveillance systems can provide important and reliable information in a timely fashion and can monitor changes in severity of influenza during a pandemic season.