Australian influenza report 2010 - 5 to 11 June 2010 (#23/10)

The Australian Influenza Report is compiled from a number of data sources, including laboratory-confirmed notifications to NNDSS, sentinel influenza-like illness reporting from general practitioners and emergency departments, workplace absenteeism, and laboratory testing. A more in-depth annual report is also published in Communicable Diseases Intelligence.

Page last updated: 21 June 2010

Report No. 23
Week ending 11 June 2010

A print friendly version of this report is available as a PDF (283 KB)

The Department of Health and Ageing acknowledges the providers of the many sources of data used in this report and greatly appreciates their contribution.

Key Indicators

The counting of every case of pandemic influenza is no longer feasible in the PROTECT phase. Influenza activity and severity in the community is instead monitored by the surveillance systems listed below.

Is the situation changing?
Indicated by trends in:
  • laboratory confirmed cases reported to the National Notifiable Diseases Surveillance System;
  • GP Sentinel influenza-like illness (ILI) Surveillance;
  • emergency department (ED) presentations for ILI;
  • ILI-related absenteeism and call centre calls: and
  • sentinel laboratory test results.
How severe is the disease, and is severity changing?
Indicated by trends in:
  • hospitalisations, ICU admissions and deaths from sentinel systems; and
  • clinical severity in hospitalised cases and ICU admissions.
Is the virus changing?
Indicated by trends in:
  • drug resistance; and
  • gene drift or shift from laboratory surveillance.


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Summary

  • Levels of influenza-like illness (ILI) in the community show signs of increasing through some surveillance systems (WA and NSW Emergency Departments, Flutracking and absenteeism).
  • Reporting from laboratories suggests that little of this community ILI is due to influenza. Respiratory syncytial virus (RSV) was the most common respiratory virus diagnosed by NSW sentinel laboratories in the last reporting period, picornavirus was most common in VIC and rhinovirus was the most common respiratory virus in WA.
  • Of the 884 confirmed cases of influenza diagnosed during 2010 up to 11 June, 9.2% have been sub-typed as pandemic (H1N1) 2009, 75.7% as type A not sub-typed (likely to be mostly pandemic influenza), 0.9% as A/H3N2 and 9.5% have been characterised as type B.
  • Sentinel hospitals have reported one hospitalisation for influenza (Pandemic, Qld) during this period, and ANZICS reported no ICU admissions for influenza A.
  • In 2010, there have been 81 confirmed cases of pandemic (H1N1) 2009 influenza reported in Australia, bringing the total of confirmed cases to 37,717 since May 2009. There has been one new confirmed case of pandemic (H1N1) 2009 influenza diagnosed and reported in Australia (Qld) during this reporting period.
  • Pandemic (H1N1) 2009 influenza virus accounted for 92.2% of all influenza A viruses subtyped globally in the last reporting period. Seasonal Influenza B viruses are now the predominant strain in the Russian Federation, China, Ukraine and Hong Kong.
  • In China, influenza B accounted for 87% of influenza viruses detected in the week to 23 May 2010. Of these, approximately 54% are the same strain as that in the 2010 Southern Hemisphere vaccine.
  • As at 23 May 2010, the WHO Regional Offices reported over 18,156 deaths associated with pandemic (H1N1) 2009 influenza worldwide. Active but declining transmission continues in the Caribbean and Southeast Asia.

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    1. Influenza activity in Australia

    Laboratory Confirmed Cases

    Pandemic influenza activity remains low and sporadic cases of pandemic influenza continue to be reported without evidence of sustained community transmission (Figure 1). There was one laboratory confirmed pandemic (H1N1) 2009 case (Qld) diagnosed during this reporting period.

    In the same period, 22 confirmed cases of influenza have been diagnosed. They included 17 of type A not sub-typed (Qld), three of type B (Qld) and one untyped (WA).

    Figure 1. Laboratory confirmed cases of pandemic (H1N1) 2009 and total influenza in Australia, to 11 June 2010

    Figure 1. Laboratory confirmed cases of pandemic (H1N1) 2009 and total influenza in Australia, to 11 June 2010

    Note: Total influenza series starts on 1 January 2010.
    Source: NetEpi (2009; NSW 2010) and NNDSS (2010)




    There have been 884 confirmed cases of influenza of all types diagnosed during 2010 up to 11 June. Of those, 81 (9.2%) have been sub-typed as pandemic (H1N1) 2009, 669 (75.7%) as influenza type A not sub-typed, 8 (0.9%) as A/H3N2 and 6 (0.7%) as type A&B. A further 84 (9.5%) have been characterised as influenza type B and 35 (4.0%) have been untyped
    (Figure 2).

    Influenza type A not further sub-typed is the predominant type in Australia to date this year. While it is expected that the majority will be pandemic (H1N1) 2009, these cases have a higher age profile (median age 45 years) than cases confirmed with the pandemic (H1N1) 2009 strain (28 years in 2010). The proportion of women diagnosed with Influenza type A not further sub-typed is also higher (51.6%) compared to that diagnosed with the pandemic (H1N1) 2009 strain (45.7%) in 2010).

    Figure 2. Laboratory confirmed cases of influenza (pandemic (H1N1) 2009 and seasonal) in Australia, 1 January 2010 to 11 June 2010, by week and type

    Figure 2. Laboratory confirmed cases of influenza (pandemic (H1N1) 2009 and seasonal) in Australia, 1 January 2010 to 11 June 2010, by week and type

    Source: NNDSS and NetEpi (NSW).


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    Influenza-Like Illness

    Sentinel General Practice Surveillance

    In the week ending 6 June 2010, national ILI consultation rates to sentinel GPs remained low and stable, with the presentation rate approximately six cases per 1,000 consultations (Figure 3). Seventy-nine GPs reported through ASPREN this reporting period.

    Figure 3. Weekly rate of ILI reported from GP ILI surveillance systems from 1 January 2007 to 6 June 2010*

    Figure 3. Weekly rate of ILI reported from GP ILI surveillance systems from 1 January 2007 to 6 June 2010

    * Delays in the reporting of data may cause data to change retrospectively. As data from the NT surveillance system is combined with ASPREN data for 2010, rates may not be directly comparable across 2007, 2008 and 2009.
    SOURCE: ASPREN, and VIDRL GP surveillance system.


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    WA Emergency Departments

    Respiratory viral presentations reported in Western Australian EDs in the week ending 13 June 2010 continue to show an upward trend (Figure 4).

    Figure 4. Number of respiratory viral presentations to Western Australia EDs from 1 January 2007 to 13 June 2010 by week

    Figure 4. Number of respiratory viral presentations to Western Australia EDs from 1 January 2007 to 13 June 2010 by week

    Source: WA ‘Virus Watch’ Report



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    NSW Emergency Departments

    In the week ending 11 June 2010, ILI presentations to NSW EDs remained low and similar to levels seen at the same time in 2007 and 2008 (Figure 5). In the month of May 2010, there were 187 ILI presentations to NSW ED’s, which was an increase from 150 in April 2010 but lower than the count of 915 for May 2009. There were 14 admissions to hospital following presentation to emergency departments with ILI in May 2010.

    Figure 5: ILI presentations to NSW EDs from 2007-2010, by week

    Figure 5: ILI presentations to NSW EDs from 2007-2010, by week

    Source: NSW Health ‘Influenza Weekly Epidemiology Report


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    Geographic spread of influenza and ILI – Jurisdictional Surveillance

    In the fortnight ending 11 June 2010, influenza and ILI activity as reported by state and territory Health Departments indicated that there was ‘no’ activity in one state (VIC) and ‘sporadic’ activity in all other states (Figure 6).

    ‘No’ activity is defined as no laboratory-confirmed cases of influenza and no increase in cases in syndromic surveillance systems. ‘Sporadic’ activity is defined as small numbers of laboratory-confirmed influenza cases or a single laboratory-confirmed influenza outbreak during the reporting period, but no increase in cases in syndromic surveillance systems.

    Figure 6. Map of influenza and ILI activity, by state and territory, during fortnight ending 11 June 2010

    Figure 6. Map of influenza and ILI activity, by state and territory, during fortnight ending 11 June 2010


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    Flutracking

    Flutracking, a national online system for collecting data on ILI in the community, reported that ILI levels remained stable in the week ending 13 June 2010. Reports are above pre-pandemic baselines (Figure 7).

    Figure 7. Rate of ILI symptoms and absence from regular duties among Flutracking participants by week, from week ending 6 June 2009 to week ending 13 June 2010

    Figure 7. Rate of ILI symptoms and absence from regular duties among Flutracking participants by week, from week ending 6 June 2009 to week ending 13 June 2010

    Source: Flutracking Interim Weekly Report



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    National Health Call Centre Network

    The number of calls to the National Health Call Centre Network (NHCCN) decreased this reporting period, and remains at baseline levels (Figure 8).

    Figure 8. Number of calls to the NHCCN related to ILI, Australia, 1 January 2009 to 11 June 2010

    Figure 8. Number of calls to the NHCCN related to ILI, Australia, 1 January 2009 to 11 June 2010

    Note: national data does not include QLD and VIC
    Source: NHCCN data



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    Deaths associated with influenza and pneumonia

    Death registration data show that as at 28 May 2010, there were 96 pneumonia or influenza deaths per 1,000 deaths in NSW, which is below the seasonal threshold of 117 per 1,000 (Figure 9).

    Figure 9. Rate of deaths classified as influenza and pneumonia from the NSW Registered Death Certificates, 2005 to 28 May 2010

    Figure 9. Rate of deaths classified as influenza and pneumonia from the NSW Registered Death Certificates, 2005 to 28 May 2010

    Source: NSW ‘Influenza Monthly Epidemiology Report’

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    Absenteeism

    In the week ending 2 June 2010, national absenteeism rates remained higher than seen in previous years (Figure 10).

    Figure 10. Rates of absenteeism (greater than 3 days absent on sick leave), national employer, from 28 January 2007 to 2 June 2010, by week

    Figure 10. Rates of absenteeism (greater than 3 days absent on sick leave), national employer, from 28 January 2007 to 2 June 2010, by week

    SOURCE: Absenteeism data


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    Sentinel Laboratory Surveillance - confirmed influenza notifications

    Results from sentinel laboratory surveillance systems for this reporting period show that only 0.3% (1/293) of the respiratory tests conducted over this period were positive for influenza (Table 1).

    Table 1. Laboratory respiratory tests that tested positive for influenza

      ASPREN* – national NSW NIC WA NIC NT
    (Reported by WA NIC)
    VIC NIC
    of specimens tested
    13
    82
    95
    N/A
    103
    Number tested which were Influenza A
    0
    0
    0
    0
    0
    Number tested which were pandemic (H1N1) 2009
    0
    0
    0
    0
    0
    Number tested which were seasonal A/H1N1
    0
    0
    0
    0
    0
    Number tested which were A/H3N2
    0
    0
    0
    0
    0
    Number tested which were Influenza A untyped
    0
    0
    0
    0
    0
    Number tested which were Influenza B
    0
    0
    1
    0
    0
    The most common respiratory virus detected
    N/A
    RSV
    rhinovirus
    N/A
    picornavirus

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    2. Overview of influenza severity to 11 June 2010*

    While pandemic (H1N1) 2009 is generally considered a mild disease at the community level, it has had serious consequences at the acute end of the disease. Figures of hospitalisations, ICU admissions and deaths are currently used as indicators of the severity of the disease in Australia (Table 2).

    * Note that while the analysis of severity is on-going, updates are presented as required when there are significant changes detected. With the current low levels of pandemic (H1N1) 2009 influenza activity in Australia it is anticipated that the indicators of pandemic severity will not vary significantly.


    Pandemic (H1N1) data for 2009 are currently being finalised through cleaning and validation processes. It is possible that these processes will result in some changes in the data presented here. Validated data will be progressively reported as these steps are completed.

    There have been a total of 37,717 confirmed cases of pandemic (H1N1) 2009 in Australia as at 11 June 2010, including 191 pandemic influenza-associated deaths. Of these, 37,636 cases were reported in 2009 and 81 cases were reported in 2010.

    Table 2. Summary of severity indicators of pandemic (H1N1) in Australia, 2009 and 2010 up to 11 June 2010

    2009# 2010a
      Confirmed pandemic
    (H1N1) 2009 cases
    Hospitalised cases ICU cases Deaths Confirmed (H1N1) 2009 cases
    Total number
    37,636
    13% (4,992/37,636) confirmed cases)
    14%
    (681/4,992 hospitalisations)
    191
    81
    Crude rate per 100,000 population
    172.1
    22.8
    3.1
    0.9
    0.4
    Median age (years)
    21
    31
    44^
    53^
    28
    Females
    51% (19,139/37,636)
    51% (2,528/4,992)
    53%
    (364/681)
    44%
    45.7%
    (37/81)
    Vulnerable groups (Indigenous persons, pregnant women & individuals with at least 1 co-morbidity)
    n/a
    58% (2,892/4,992)
    74%
    (504/681)
    67%
    n/a
    Indigenous people~
    11% (3,877/34,750)
    20%
    (808/4,048)
    19%
    (102/533)
    13%
    3.6%
    (2/56)
    Pregnant women*
    n/a
    27%
    (287/1,056 hospitalised females aged
    15-44 years)
    16%
    (47/289) hospitalised pregnant women)
    4%
    n/a
    Cases with at least 1 co-morbidity
    n/a
    46% (2,303/4,992)
    67%
    (457/681)
    62%
    n/a

    a Data for 2009 from NetEpi, Data for 2010 from NNDSS and NetEpi (NSW).
    #Data are extracted from a number of sources depending on the availability of information. Figures used in the analysis have been provided in parentheses. Data are not always complete for each summarised figure.
    ~The denominator for this row is the number of confirmed cases for which Indigenous status is known. In 2010, 25 cases had Indigenous status unknown.
    * Includes women in the post-partum period.
    ^ Validation of data has identified anomalies affecting median ages for ICU cases and deaths in reports #28-33 2009 and report #1 2010. Correction has resulted in a change in the median ages of ICU cases and deaths from report #2, 2010.
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    Influenza Hospitalisations

    The Influenza Complications Alert Network (FluCAN) reported one influenza hospitalisation from selected hospitals (Pandemic, in Qld) for the week ending 11 June 2010. For the period of 1 March to 11 June 2010, FluCAN has reported a total of 10 influenza hospitalisations (Table 3 and Figure 11). Of those, four have been associated with pandemic (H1N1) 2009, including two with ICU admission.

    Table 3. Number of influenza hospitalisations, sentinel hospitals, Australia, 1 March to 11 June 2010

    Type of influenza
    Week ending
    11 June 2010
    Total
    1 March – 11 June
    Pandemic (H1N1)
    1
    5
    Type A/H3N2
    0
    1
    Type B
    0
    3
    Type A not subtyped
    0
    1
    All types
    1
    10

    Source: Influenza Complications Alert Network (FluCAN). Data are from 10 sentinel hospitals from all jurisdictions except NT.



    Figure 11. Number of influenza hospitalisations, sentinel hospitals, Australia, 1 March to 11 June 2010

    Figure 11. Number of influenza hospitalisations, sentinel hospitals, Australia, 1 March to 11 June 2010

    Source: FluCAN data from 10 sentinel hospitals in all jurisdictions except NT


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    Intensive care

    The Australian and New Zealand Intensive Care Society (ANZICS) has reported a total of seven ICU admissions for influenza in 2010, and none for this reporting period. Of these, three have been associated with pandemic (H1N1) 2009 influenza and four with Type A not further sub-typed (Figure 12).

    Figure 12. Number of ICU admissions for influenza, ANZICS, Australia, 1 January to 11 June 2010

    Figure 12. Number of ICU admissions for influenza, ANZICS, Australia, 1 January to 11 June 2010

    Source: Australian and New Zealand Intensive Care Society (ANZIC) data base


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    3. Virology

    Antigenic characteristics - WHO Collaborating Centre for Reference & Research on Influenza (WHO CC) in Melbourne

    From 1 January 2010 to 13 June 2010, there were 34 Australian influenza isolates subtyped by the WHO CC (Table 4).

    Table 4. Typing of influenza isolates from the WHO Collaborating Centre, from 1 January 2010 to 13 June 2010


    Type/Subtype
    ACT NSW NT Qld SA Tas Vic WA TOTAL
    A(H1N1)
    0
    0
    0
    0
    0
    0
    0
    0
    0
    Pandemic (H1N1) 2009
    1
    0
    3
    7
    0
    1
    7
    2
    21
    A(H3N2)
    0
    0
    0
    0
    0
    0
    4
    0
    4
    B
    0
    0
    0
    0
    0
    0
    9
    0
    9
    Total
    1
    0
    3
    7
    0
    1
    20
    2
    33

    SOURCE: WHO CC
    Please note: There may be up to a month delay on reporting of samples.
    Isolates tested by the WHO CC are not necessarily a random sample of all those in the community, hence proportions of pandemic (H1N1) 2009 to seasonal are not representative of the proportions circulating.

    Antigenic characterisation of 12 Pandemic (H1N1) 2009 isolates has shown 11 to be the A/California/7/2009-like strain and one a low reactor version of this strain. Antigenic characterisation of 1 type A/H3N2 isolate has shown to be the A/Perth/16/2009-like low reactor version of the strain.
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    International Updates

    In the week ending 29 May 2010, based on FluNet reporting by National influenza Centres from 18 countries, 58.5% of positive specimens were typed as influenza B and 41.5% were typed as influenza A. Pandemic (H1N1) 2009 influenza virus accounted for 92.2% of all influenza A viruses subtyped globally by the WHO Collaborating Centres in the week ending 11 June 2010. In some parts of Africa, however, the proportion of A(H3N2) virus detections have exceeded that of pandemic (H1N1). Sporadic A(H3N2) was reported from some parts of Africa, Australia and China. Seasonal Influenza B viruses are the predominant influenza virus in Hong Kong, China, the Russian Federation and Ukraine.1

    In China, influenza B accounted for 89.4% of all influenza viruses detected in the week to 30 May 2010. From 1 September 2009 to 30 May 2010, 3907 influenza B viruses have been antigenically characterised. Of those, 3514 (89.9%) were B/Victoria viruses, including 45.6% (1604) related to B/Malaysia/2506/2004-like and 54.4% (1910) related to B/Brisbane/60/2008 (included in 2010 Southern Hemisphere seasonal influenza vaccine). The remaining 393 (10.1%) were B/Yamagata viruses related to B/Florida/4/2006-like.2
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    Antiviral Resistance

    Pandemic (H1N1) 2009

    The WHO has reported that 298 oseltamivir resistant pandemic (H1N1) 2009 viruses have been detected and characterised worldwide. All but one of these isolates showed the same H275Y mutation but were sensitive to zanamivir.1
    The WHO Collaborating Centre in Melbourne has reported that from 1 January 2010 to 13 June 2010, no isolates (out of 10 tested) have shown resistance to oseltamivir by enzyme inhibition assay (EIA) and two isolates (out of 15 tested) have shown the H275Y mutation known to confer resistance to oseltamivir.
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    4. International Influenza Surveillance

    WHO Summary as at 6 June 2010

    There have been over 18,156 deaths associated with pandemic (H1N1) 2009 worldwide.
    • Northern Hemisphere
      • Active but declining transmission of pandemic influenza virus continues in parts of the Caribbean and Southeast Asia.
      • Overall pandemic influenza activity remains low.
      • Seasonal influenza type B viruses:
        • are the predominant type of influenza virus circulating globally
        • are circulating at low levels.
    • Southern Hemisphere
      • Pandemic and seasonal influenza activity is sporadic.
      • ILI remains low in Australia and New Zealand.
      • A small number of pandemic influenza virus detections in Chile and Uraguay.
      • Sporadic A(H3N2) was reported from some parts of Africa, Australia and China.

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    5. Data considerations

    The information in this report is reliant on the surveillance sources available to the Department of Health and Ageing. As access to sources increase and improve, this report will be refined and additional information will be included.

    This report aims to increase awareness of pandemic (H1N1) 2009 and seasonal influenza in Australia by providing an analysis of the various surveillance data sources throughout Australia. While every care has been taken in preparing this report, the Commonwealth does not accept liability for any injury or loss or damage arising from the use of, or reliance upon, the content of the report. Delays in the reporting of data may cause data to change retrospectively. For further details about information contained in this report please contact the Influenza Team through flu@health.gov.au

    On 17 June 2009 Australia commenced the transition to a new response phase called PROTECT, in which laboratory testing is directed towards people with moderate or severe illness; those more vulnerable to severe illness; and those in institutional settings. This means that the number of confirmed cases does not reflect how many people in the community have acquired pandemic (H1N1) 2009 infection.

    NetEpi

    In 2009, NetEpi, a web-based outbreak case reporting system for pandemic (H1N1) 2009, was used as the primary source of enhanced data on confirmed cases, hospitalisations and ICU admissions in all jurisdictions. In 2010, only data for NSW are sourced from NetEpi.

    Analyses of Australian cases are based on the diagnosis date, which is the earliest of the onset date, specimen date or notification date.

    National Notifiable Diseases Surveillance System (NNDSS)

    Laboratory confirmed influenza (all types) is notifiable in all jurisdictions in Australia. Confirmed cases of influenza are notified through NNDSS by all jurisdictions except NSW. NSW data are sourced from NetEpi.

    Data Analysis

    Analysis of confirmed influenza cases is conducted on combined NetEpi and NNDSS data. Analysis of morbidity (hospitalisations and ICU admissions) and mortality data in 2009 has been conducted on combined NetEpi and QLD hospitalisation data.

    Laboratory Surveillance data

    Laboratory testing data are extracted from the ‘NSW Influenza Report,’ and the ‘The 2009 Victorian Influenza Vaccine Effectiveness Audit Report’ (VIDRL) ‘South Australian Seasonal Influenza Report’. These reports are provided weekly.

    WHO Collaborating Centre for Reference & Research on Influenza (WHO CC)

    Data are provided weekly to the Surveillance Branch from the WHO CC.
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    Sentinel General Practice Surveillance

    The Australian Sentinel Practices Research Network (ASPREN) has Sentinel GPs who report ILI presentation rates in NSW, SA, ACT, VIC, QLD, TAS and WA. As jurisdictions joined ASPREN at different times and the number of GPs reporting has changed over time, the representativeness of ASPREN data in 2009 may be different from that of previous years. ASPREN data are sent to the Surveillance Branch on a weekly basis. Northern Territory GP surveillance data are sent to the Surveillance Branch on a weekly basis. VIDRL influenza surveillance data are sent to the Surveillance Branch on a weekly basis.
    Further information on Sentinel GPs’ Influenza Surveillance and ASPREN activities are available at www.dmac.adelaide.edu.au/aspren

    Sentinel ED data

    WA - ED surveillance data are extracted from the ‘Virus Watch’ Report. This report is provided weekly. The Western Australia Influenza Surveillance Program collects data from eight Perth EDs.
    NSW - ED surveillance data are extracted from the ‘Influenza Monthly Epidemiology Report, NSW’. This report is provided monthly. The New South Wales Influenza Surveillance Program collects data from 49 EDs across New South Wales.

    Absenteeism

    A national organisation provides data on the number of employees who have been on sick leave for a continuous period of more than three days. These data are not influenza or ILI specific and absenteeism may be a result of other illnesses.

    National Health Call Centre Network

    A national organisation provides call centre data for calls relating to ILI or influenza. Data are provided daily and are collated weekly and have been presented in this report to show the pattern of calls to this Call Centre over the 2009 season. Data is available for all jurisdictions other than QLD and VIC.

    FluTracking

    FluTracking is a project of the University of Newcastle, the Hunter New England Area Health Service and the Hunter Medical Research Institute. FluTracking is an online health surveillance system to detect epidemics of influenza. It involves participants from around Australia completing a simple online weekly survey, which collects data on the rate of ILI symptoms in communities.
    Data have been provided weekly and have been presented in this report to show the pattern of self reported ILI in the community over the 2009 season.

    Further information on FluTracking is available at www.flutracking.net/index.html

    FluCAN

    The Influenza Complications Network (FluCAN) collects detailed clinical information on all hospitalised cases of influenza and pneumonia from a sample of 15 sentinel hospitals across Australia. The data for this reporting period are sourced only from 11 hospitals and do not include NT.

    Australian and New Zealand Intensive Care Society data (ANZICS data)

    The Australian and New Zealand Intensive Care Society provides data from a `near real time` registry of patients admitted to Australian ICUs. This documents the key factors influencing mortality, as well as the need for hospitalisation and mechanical ventilation. Information collected includes person characteristics and information on relevant co-morbidities, nature of the clinical syndrome associated with pandemic (H1N1) 2009, major therapeutic interventions from which organ failure outcomes can be imputed, vaccination status and vital status at time of ICU discharge and hospital discharge.

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    6. References

    WHO Pandemic (H1N1) 2009 - Update 104 & Virological Surveillance Weekly Update. Available from http://www.who.int/csr/don/en/ Accessed 17 June 2010.
    Chinese National Influenza Centre Influenza Weekly Report 30 May 2010. Available from: http://www.cnic.org.cn/eng/ Accessed 17 June 2010.