Australian influenza report 2012 - 26 May - 8 June 2012 (#1/12)

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: 14 April 2011

Report No. 1
Week ending 8 June 2012

PDF printable version of Australian Influenza Surveillance Report No 1 - 2012 (PDF 824 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

Influenza activity and severity in the community is monitored using the following indicators and surveillance systems:

Is the situation changing?Indicated by trends in:
    • laboratory confirmed cases reported to the National Notifiable Diseases Surveillance System (NNDSS);
    • general practitioner (GP) consultations for influenza-like illness (ILI);
    • emergency department (ED) presentations for ILI;
    • ILI-related call centre calls and community level surveys of ILI; and
    • sentinel laboratory test results.
How severe is the disease, and is severity changing?Indicated by trends in:
    • hospitalisations, intensive care unit (ICU) admissions and deaths; and
    • clinical severity in hospitalised cases and ICU admissions.
Is the virus changing?Indicated by trends in:
    • drug resistance; and
    • antigenic drift or shift of the circulating viruses.

Summary


Across all surveillance systems, influenza activity this fortnight has increased.
  • The majority of states have reported localised increases in influenza detections above background levels, with New South Wales, South Australia and the centre of the Northern Territory reporting significant recent increases in activity.
  • Seasonal influenza-like illness (ILI) activity in the community has started to increase slightly earlier than in previous years (excluding 2009).
  • During this fortnight there were 1,138 laboratory confirmed notifications of influenza, with New South Wales, Queensland and South Australia reporting the highest number of notifications.
  • Nationally, influenza A(H3N2) is the predominant circulating strain with some co-circulation of influenza B also occurring. Influenza A(H3N2) is predominant across most states and territories, however influenza B represents around two-thirds and half of all notifications in the Northern Territory and Western Australia, respectively. So far in 2012 there have been very few notifications of pandemic (H1N1) 2009.
  • As at 8 June 2012, there have been 3,687 confirmed cases of influenza reported to the National Notifiable Diseases Surveillance System (NNDSS). Compared with 2011, the 2012 influenza activity during the inter-seasonal period remained relatively low. Excluding 2009, notifications of influenza in 2012 have started their seasonal increase slightly earlier in comparison with previous years.
  • The WHO has reported that worldwide influenza activity is generally low. Activity in the northern hemisphere is continuing to decline to baseline levels and activity within the southern hemisphere is still low. Globally there is variable predominance of influenza A(H3N2) and influenza B viruses, with very low numbers of pandemic (H1N1) 2009 detections.
Top of Page

    1. Geographic Spread of Influenza Activity in Australia


    In the fortnight ending 8 June 2012, the geographic spread of influenza activity reported by state and territory Health Departments was ‘sporadic’ in the ACT and Tasmania; ‘localised’ in the top end of the NT, central and southern Queensland, Victoria and WA; and ‘widespread’ in NSW, SA and the centre of the NT (figure 1). During this period, NSW, the NT, Queensland and WA had evidence of an increase in ILI via syndromic surveillance systems. Definitions of these activity levels are provided in the Data Considerations section of this report.

    Figure 1. Map of influenza activity by state and territory during the fortnight ending 8 June 2012
    Figure 1. Map of influenza activity by state and territory during the fortnight ending 8 June 2012 - see description above

    2. Influenza-like illness activity


    Community Level Surveillance


    FluTracking

    FluTracking, a national online system for collecting data on ILI in the community, noted that in the week ending 10 June 2012 fever and cough was reported by 2.8% of vaccinated participants and 3.0% of unvaccinated participants (figure 2). FluTracking Weekly Interim Report #6, 10 June 2012. Available from: http://www1.hnehealth.nsw.gov.au/hneph/HNEPHApplications/FluSurvey/Reports/LatestReport.pdf. Accessed 15 June 2012. Fever, cough and absence from normal duties was reported by 1.6% of vaccinated participants and 1.5% of unvaccinated participants. Current rates of ILI among FluTracking participants are relatively consistent with previous years (figure 3).
    Top of Page
    Up to 10 June 2012, 51.8% of participants reported having received the seasonal vaccine so far. Of the 2,139 participants who identified as working face-to-face with patients, 71.3% have received the vaccine.

    Figure 2. Proportion of cough and fever among Flutracking participants by week and vaccination status, from week ending 6 May 2012 to week ending 10 June 2012
    Figure 2. Proportion of cough and fever among Flutracking participants by week and vaccination status, from week ending 6 May 2012 to week ending 10 June 2012 - see description above
    Source: FluTracking1

    Figure 3. Proportion of fever and cough among FluTracking participants by week, between May and October, 2008 to 2012
    Figure 3. Proportion of fever and cough among FluTracking participants by week, between May and October, 2008 to 2012 - see description above
    Source: FluTracking1
    National Health Call Centre Network
    Top of Page
    The number of ILI related calls to the National Health Call Centre Network (NHCCN) continued to increase this fortnight. In the week ending 10 June 2012, the percentage of total calls which were ILI related increased to 9.3%, which is slightly higher than the same period in 2011 (figure 4).

    Figure 4. Number of calls to the NHCCN related to ILI and percentage of total calls, Australia, 1 January 2010 to 10 June 2012
    Figure 4. Number of calls to the NHCCN related to ILI and percentage of total calls, Australia, 1 January 2010 to 10 June 2012 - see description above
    Note: National data do not include Queensland (2010-2012) and Victoria (2010-2011)
    Source: NHCCN data

    Sentinel General Practice Surveillance


    Sentinel general practitioner ILI consultation rates have continued to increase this fortnight. In the week ending 10 June 2012, the national ILI consultation rate to sentinel GPs was 13.4 cases per 1,000 consultations, up from 8.3 cases per 1,000 in the previous fortnight (figure 5). Compared with previous years (excluding 2009) there has been a slightly earlier increase in seasonal ILI consultation rates.

    Figure 5. Weekly rate of ILI reported from GP ILI surveillance systems from 1 January 2008 to 10 June 2012*Top of Page
    Figure 5. Weekly rate of ILI reported from GP ILI surveillance systems from 1 January 2008 to 10 June 2012 - see description above
    * Delays in the reporting of data may cause data to change retrospectively. As data from the previous Northern Territory surveillance system was combined with ASPREN and VIDRL surveillance data for 2008 and 2009, rates may not be directly comparable with 2010-2012.
    SOURCE: ASPREN and VIDRL GP surveillance system The 2012 Victorian Influenza Vaccine Effectiveness Audit Report #6, 10 June 2012. Available from: www.victorianflusurveillance.com.au. Accessed 15 June 2012..

    In the fortnight ending 10 June 2012, specimens were collected from almost half of ASPREN ILI patients. Of these patients, 28% were positive for influenza, up from 17% in the previous fortnight. Twenty percent were positive for influenza type A, with the majority likely to be attributed to A (H3N2); and the remaining 8% were influenza type B (figure 6 and table 1). Almost a third of specimens collected were positive for other respiratory viruses, with the majority of these being either rhinovirus or RSV.

    Table 1. ASPREN laboratory respiratory viral test results of I LI consultations, 1 January 2012 to 10 June 2012.Top of Page
          Fortnight
          (28 May to 10 June 2012)
          YTD
          (1 January – 10 June 2012)
    Total specimens tested182665
    Total Influenza Positive (%)27.517.9
    Influenza A (%)19.812.2
    Pandemic (H1N1) 2009 (%)0.00.2
    Influenza A (unsubtyped) (%) #19.812.0
    Influenza B (%)7.75.7
    Other Resp. Viruses (%)*31.329.3
    # The majority of type A(unsubtyped) notifications are likely to be attributed to A(H3N2)
    * Other respiratory viruses include RSV, parainfluenza, adenovirus and rhinovirus.

    Figure 6. Proportion of respiratory viral tests positive for influenza in ILI patients and GP ILI consultation rate, by week, 1 January 2012 to 10 June 2012
    Figure 6. Proportion of respiratory viral tests positive for influenza in ILI patients and GP ILI consultation rate, by week, 1 January 2012 to 10 June 2012 - see description above
    SOURCE: ASPREN and WA SPN

    Sentinel Emergency Department Surveillance

    Top of Page
    Western Australia Emergency Departments

    In the fortnight ending 10 June 2012, respiratory viral presentations to WA emergency departments continued to increase, and presentations remain well above baseline levels (figure 7). Over this period there were 1,279 presentations, including 77 admissions. The proportion of presentations admitted to hospital over this period decreased to 6.0%, compared with 7.6% in the previous fortnight.

    Figure 7. Number of respiratory viral presentations to Western Australia emergency departments from 1 January 2008 to 10 June 2012, by week
    Figure 7.	Number of respiratory viral presentations to Western Australia emergency departments from 1 January 2008 to 10 June 2012, by week - see description above
    Source: WA ‘Virus Watch’ Report WA Virus Watch Report, 10 June 2012. Available from: http://www.public.health.wa.gov.au/cproot/4604/2/20120610_virus_watch.pdf. Accessed 15 June 2012.
    New South Wales Emergency Departments

    In the week ending 8 June 2012 the number of patients presenting to NSW emergency departments (EDs) with ILI increased and was above the usual range for this time of year (figure 8). The majority (32%) of ILI presentations were reported in people aged 25 to 34 years of age, and well people in the age ranges of 15-24, 35-44 and 55-64 years reported a higher number of attendances. Total admissions from ED to critical care units for ILI and pneumonia decreased this week, and remained above the usual range for this time of year. NSW Influenza Weekly Epidemiology Report, 2 to 8 June 2012. Available from: http://www.health.nsw.gov.au/resources/publichealth/infectious/influenza/pdf/weekending_08062012l.pdf. Accessed 15 June 2012.Top of Page

    Figure 8. Rate of influenza-like illness presentations to New South Wales emergency departments, between May and October, 2008 to 2012, by week*
    Figure 8. Rate of influenza-like illness presentations to New South Wales emergency departments, between May and October, 2008 to 2012, by week - see description above
    Source: NSW Influenza Weekly Epidemiology Report3
    *Data missing for weeks 34-35 in 2011
    Northern Territory Emergency Departments

    In the fortnight ending 9 June 2012, the number of patients presenting to emergency departments across the Northern Territory was 488, which is slightly above the number of presentations observed in previous years over the same period (figure 9).

    Figure 9. Number of respiratory viral presentations to Northern Territory emergency departments, 1 January 2008 to 10 June 2012, by weekTop of Page

    Figure 9.	Number of respiratory viral presentations to Northern Territory emergency departments, 1 January 2008 to 10 June 2012, by week - see description above
    Source: Centre for Disease Control, Department of Health, Northern Territory Government

    3. Laboratory confirmed influenza activity


    Notifications of Influenza to Health Departments


    During the reporting period there were 1,138 laboratory confirmed influenza notifications reported to the NNDSS. Of these notifications, there were 371 in NSW, 320 in Queensland, 202 in SA, 106 in Victoria, 88 in WA, 37 in the NT, 10 in the ACT and 4 in Tasmania (figure 10). A weekly breakdown of trends by state and territory highlights that notifications have been highest in New South Wales, Queensland and South Australia. Notifications are continuing to increase across most states and territories (figure 11).
    Figure 10. Laboratory confirmed cases of influenza in Australia, 1 January to 8 June 2012, by state, by week.Top of Page
    Figure 10. Laboratory confirmed cases of influenza in Australia, 1 January to 8 June 2012, by state, by week - see description above Source: NNDSS

    Figure 11. State breakdowns of laboratory confirmed cases of influenza, 1 January to 8 June 2012, by weekTop of Page

    NSW breakdown of laboratory confirmed cases of influenza, 1 January to 8 June 2012, by week - see description aboveACT breakdown of laboratory confirmed cases of influenza, 1 January to 8 June 2012, by week - see description aboveQLD breakdown of laboratory confirmed cases of influenza, 1 January to 8 June 2012, by week - see description aboveNT breakdown of laboratory confirmed cases of influenza, 1 January to 8 June 2012, by week - see description aboveSA breakdown of laboratory confirmed cases of influenza, 1 January to 8 June 2012, by weekTAS breakdown of laboratory confirmed cases of influenza, 1 January to 8 June 2012, by week - see description aboveWA breakdown of laboratory confirmed cases of influenza, 1 January to 8 June 2012, by week - see description aboveVIC breakdown of laboratory confirmed cases of influenza, 1 January to 8 June 2012, by week - see description above
    Source: NNDSS

    Up to 8 June, there have been 3,687 laboratory confirmed notifications of influenza diagnosed during 2012 (figure 12). Of these notifications, there have been 1,104 notified in Queensland, 889 in NSW, 556 in WA, 485 in SA, 476 in Victoria, 115 in the NT, 42 in the ACT and 20 in Tasmania.

    Figure 12. Laboratory confirmed cases of influenza in Australia, 1 January 2008 to 8 June 2012Top of Page
    Figure 12. Laboratory confirmed cases of influenza in Australia, 1 January 2008 to 8 June 2012 - see description above
    Source: NNDSS
    Top of Page
    Of the 1,138 influenza notifications reported to the NNDSS this reporting period, 914 were influenza A (671 were influenza A (unsubtyped), 228 were A(H3N2), 8 were pandemic (H1N1) 2009 and 7 were A (not pandemic)), 218 were influenza B and 6 notifications were reported as A&B or untyped (figure 13). The majority of type A (unsubtyped) notifications are likely to be attributed to A(H3N2).

    Nationally, influenza A(H3N2) is the predominant circulating strain with some co-circulation of influenza B also occurring. Influenza A(H3N2) is predominant across most states and territories, however influenza B represents around two-thirds and half of notifications in the Northern Territory and Western Australia, respectively. So far in 2012 there have been very few notifications of pandemic (H1N1) 2009 reported.

    So far in 2012, 2,720 (74%) cases were reported as influenza A (54% influenza A (unsubtyped), 18% A(H3N2), 2% pandemic (H1N1) 2009 and <1% A (not pandemic)) and 923 (25%) were influenza B. A further 19 (<1%) were influenza type A&B and 25 (<1%) were untyped (figure 13).

    Figure 13. Laboratory confirmed cases of influenza in Australia, 1 January to 8 June 2012, by sub-type and weekTop of Page
    Figure 13. Laboratory confirmed cases of influenza in Australia, 1 January to 8 June 2012, by sub-type and week - see description above
    Source: NNDSS

    Sentinel Laboratory Surveillance

    Top of Page
    Results from sentinel laboratory surveillance systems for this reporting period show that 8.4% of the respiratory viral tests conducted over this period were positive for influenza (table 2). Influenza A(H3N2) was the predominant influenza virus reported through sentinel laboratory surveillance systems this fortnight. A breakdown of subtypes within this positive proportion by fortnight is highlighted in figure 14.

    Table 2. Sentinel laboratory respiratory virus testing results, 26 May to 8 June 2012
    NSW NIC*WA NICNT
    (Reported by WA NIC)
    VIC NICTAS
    (PCR Testing Data)
    Total specimens tested3235391024531
    Total Influenza Positive33416134
    Positive Influenza A32386104
    Pandemic (H1N1) 200910020
    A(H3N2)1738380
    Influenza A unsubtyped140004
    Positive Influenza B123030
    Proportion Influenza Positive (%)10.27.660.05.312.9
    Most common respiratory virus detected-RSV
    A (H3N2)
    -Picornavirus-

    Figure 14. Proportion of sentinel laboratory tests positive for influenza, by subtype and fortnight, 26 May to 6 June 2012Top of Page
    Figure 14. Proportion of sentinel laboratory tests positive for influenza, by subtype and fortnight, 26 May to 6 June 2012 - see description above
    Source: National Influenza Centres (WA, Vic, NSW) and Tasmanian laboratories (PCR testing)

    Hospitalisations

    Top of Page
    Influenza Complications Alert Network (FluCAN)

    The Influenza Complications Alert Network (FluCAN) sentinel hospital system has reported 70 hospitalisations, including 4 ICU admissions, associated with influenza between 7 April and 8 June (figure 15). Admitted cases to reporting hospitals have been relatively young (mean age 42 years), with 67% reporting known medical co-morbidities. So far, the highest number of influenza hospitalisations have been reported from Alice Springs Hospital, with almost all cases being influenza B. This is consistent with current seasonal activity that is occurring in the centre of the Northern Territory; whereas influenza activity has only recently started to increase elsewhere.

    Figure 15. Number of influenza hospitalisations at sentinel hospitals, by week and influenza subtype, 7 April to 8 June 2012Top of Page
    Figure 15. Number of influenza hospitalisations at sentinel hospitals, by week and influenza subtype, 7 April to 8 June 2012 - see description above
    Source: FluCAN Sentinel Hospitals

    Queensland Public Hospital Admissions (EpiLog)
    Top of Page
    Admissions to public hospitals in Queensland of confirmed influenza are detected through the EpiLog system. The number of admissions for weeks 22 to 24 (inclusive) accounted for approximately 24% of the total admissions so far in 2012 (22/90), however there is no obvious trend at this time (figure 16). So far in 2012, the highest number of hospitalisations have been in the 0-4 year age group (22), followed by the 70-79 year age group (12). The median age of hospitalisations was 33 years, range <1 to 102 years.

    Figure 16. Number of influenza admissions to Queensland public hospitals, by week and type of admission, with onset from 1 January to 10 June 2012
    Figure 16. Number of influenza admissions to Queensland public hospitals, by week and type of admission, with onset from 1 January to 10 June 2012
    Source: Queensland Health EpiLog data

    Deaths associated with influenza and pneumonia

    Top of Page
    Nationally Notified Influenza Associated Deaths

    So far in 2012, 6 influenza associated deaths have been notified to the NNDSS, with a median age of 75 years. All cases were reported as having influenza A (unsubtyped) and are likely to be attributable to A (H3N2) infections.

    New South Wales Influenza and Pneumonia Death Registrations

    Death registration data up to 25 May 2012 showed that there were 0.9 pneumonia or influenza associated deaths per 100,000 population in NSW, which is below the seasonal threshold of 1.6 per 100,000 NSW population for this period (Figure 17).4

    Figure 17. Rate of deaths classified as influenza and pneumonia from the NSW Registered Death Certificates, 1 January 2007 to 25 May 2012
    Figure 17. Rate of deaths classified as influenza and pneumonia from the NSW Registered Death Certificates, 1 January 2007 to 25 May 2012 - see description above
    Source: NSW ‘Influenza Weekly Epidemiology Report’4

    4. Virological Surveillance

    Top of Page

    Typing and antigenic characterisation


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

    From 1 January to 12 June 2012, there were 274 Australian influenza viruses subtyped by the WHO CC with an equal split these viruses subtyped as influenza A(H3N2) and influenza B. So far this year, very few viruses have been subtyped as pandemic (H1N1) 2009 (table 3).

    Table 3. Australian Influenza viruses typed by HI or PCR from the WHO Collaborating Centre, from 1 January 2012 to 12 June 2012Top of Page
    Type/SubtypeACTNSWNTQLDSATASVICWATOTAL
    Pandemic (H1N1) 20090012002510
    A(H3N2)0320412222312132
    B0827211722136132
    Total04028643944653274
    SOURCE: WHO CC
    Please note: There may be up to a month delay on reporting of samples.
    Viruses tested by the WHO CC are not necessarily a random sample of all those in the community.

    The WHOCC has analysed some of the currently circulating influenza viruses. Whilst the majority of the influenza A(H3N2) viruses are of a more recent strain that differs from the A(H3N2) strain in the 2012 Southern Hemisphere seasonal influenza vaccine, it is expected that the vaccine will still offer significant protection. Additionally we are currently seeing some co-circulation of the two influenza B lineages. The majority of influenza B viruses are of the B/Victoria lineage and are similar to the strain in the current vaccine. Some cross-protection against influenza B viruses of the other (B/Yamagata) lineage is expected in adults, though less so for children. The next northern hemisphere vaccine (2012-13) will include a B/Yamagata lineage virus instead of the current B/Victoria lineage virus.

    Antiviral Resistance


    The WHO CC has reported that from 1 January to 12 June 2012, one influenza virus (out of 194 tested) has shown resistance to the neuraminidase inhibitor oseltamivir. This virus was a pandemic (H1N1) 2009 virus with H275Y mutation in the neuraminidase gene, which is known to confer resistance to oseltamivir.

    2012/13 Northern Hemisphere Vaccine


    In February 2012 the WHO recommended that vaccines for the 2012-2013 influenza season (northern hemisphere winter) contain the following: In comparison to the current 2012 southern hemisphere vaccine, the recommended A(H3N2) and B viruses have been changed. The WHO notes in their recommendations that5:
      • the majority of recent A(H3N2) viruses were antigenically and genetically distinguishable from the current southern hemisphere vaccine virus (A/Perth/16/2009) and were more closely related to A/Victoria/361/2011-like reference viruses.
      • the proportion of B/Yamagata/16/88 lineage viruses increased in many parts of the world but B/Victoria/2/87 lineage viruses predominated in some countries. The majority of recent B/Victoria/2/87 lineage viruses were antigenically and genetically closely related to the current southern hemisphere vaccine virus (B/Brisbane/60/2008). Most recently isolated B/Yamagata/16/88 lineage viruses were antigenically distinguishable from the previous vaccine virus B/Florida/4/2006 and were closely related to B/Wisconsin/1/2010-like viruses.

    5. International Influenza Surveillance

    Top of Page
    The WHO WHO Influenza Update 161 (8 June 2012). Available from: http://www.who.int/influenza/surveillance_monitoring/updates/latest_update_GIP_surveillance/en/index.html#. Accessed 15 June 2012. has reported that as at 8 June 2012 worldwide influenza activity is generally low. In the temperate regions of the northern hemisphere, influenza activity is continuing to decline back to baseline levels, indicating that the season is ending. In the tropical areas of the world, influenza activity is low, with the exception of China Hong Kong Special Administrative Region and Madagascar, where influenza A(H3N2) is the predominantly circulating virus.

    Influenza activity in the temperate zone of the southern hemisphere is still low. Chile and Paraguay have reported increasing ILI activity over the past couple of weeks and of the specimens tested influenza A(H3N2) has been the predominant influenza virus detected in Chile and pandemic (H1N1) 2009 in Paraguay.

    In New Zealand New Zealand Influenza Weekly Update, 4 to 10 June 2012. Available from: http://www.surv.esr.cri.nz/virology/influenza_weekly_update.php, Accessed 15 June 2012. , for the week ending 10 June 2012, the national rate of ILI consultations were below the baseline level of activity, however, 7 of the twenty district health boards were above the national average weekly consultation rate. Virological surveillance through both sentinel and non-sentinel laboratories shows that so far this year there has been an almost equal split between influenza A(H3N2) and B virus detections, with very few pandemic (H1N1) 2009 viruses detected. The majority of circulating influenza strains are noted as being covered by the 2012 southern hemisphere vaccine.

    National Influenza Centres and laboratories in 82 countries, areas or territories, have reported that for the period 13 May to 26 May 2012, a total of 2,297 specimens were reported as positive for influenza viruses, with 74% being influenza A and 26% influenza B. Of the sub-typed influenza A viruses reported, 89% were influenza A(H3N2) and 11% were pandemic (H1N1) 2009 WHO Laboratory confirmed data from the Global Influenza Surveillance Network – 8 June 2012. Available from: http://www.who.int/influenza/gisrs_laboratory/updates/summaryreport/en/index.html. Accessed 15 June 2012.

    . Of the characterised influenza B viruses, 61% belong to the B/Yamagata lineage and 39% to the B/Victoria lineage.

    6. Data considerations

    Top of Page
    The information in this report is reliant on the surveillance sources available to the Department of Health and Ageing. As access to sources increase as the season progresses, this report will be updated with the additional information.

    This report aims to increase awareness of influenza activity 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 Surveillance Team through flu@health.gov.au.

    Geographic Spread of Influenza Activity


    Influenza Activity Levels
    Activity levelLaboratory notifications Influenza outbreaks
    SporadicSmall no of lab confirmed influenza detections (not above expected background level)+ ANDNo outbreaks
    LocalisedRecent increase in lab confirmed influenza detections above background level ++ in less than 50% of the influenza surveillance regions** within the state or area ORSingle outbreak only
    RegionalSignificant*** recent increase in lab confirmed influenza detections above baseline in less than 50% of the influenza surveillance regions within the state or area OR> 1 outbreaks occurring in less than 50% of the influenza surveillance regions within the state or area+++
    Widespread Significant recent increase in lab confirmed influenza detections above baseline in equal to or greater than 50% of the influenza surveillance regions within the state or areaOR> 1 outbreaks occurring in equal to or greater than 50% of the influenza surveillance regions within the state or area
    + Small no of lab detections = not above expected background level as defined by state epidemiologists.
    ++ Increase in lab confirmed influenza detections = above expected threshold as defined by state epidemiologists.
    ** Influenza surveillance region within the state/area as defined by state epidemiologists.
    *** Significant increase is a second threshold to be determined by the state epidemiologists to indicate level is significantly above the expected baseline.
    +++ Areas to be subdivision of NT (2 regions), WA (3 regions) and QLD (3 regions) that reflect significant climatic differences within those states resulting in differences in the timing of seasonal influenza activity on a regular basis.
    Recent = within the current reporting period.

    Syndromic Surveillance Activity
    Top of Page
    Syndromic surveillance systems*
    No evidence of increase in ILI via syndromic surveillance systems
    Evidence of increase in ILI via syndromic surveillance systems
    * Syndromic surveillance systems = GP sentinel surveillance, ED ILI surveillance, Flu tracking (this may be due to a variety of respiratory viruses so the report could add a note to indicate if other evidence suggests that the increase is suspected to be influenza activity or due to another respiratory pathogen). .Syndromic surveillance is reported on a state wide basis only

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

    FluTracking investigators found that at the community level, peak ILI levels for 2007 were higher than 2009 This finding was consistent with other surveillance systems measuring ILI at the community level, with ASPREN showing similar levels of peak ILI in 2007 and 2009; Google flu trends showed higher levels of ILI at the peak in 2007 as compared to 2009; and workplace absenteeism showed slightly higher peak levels of ILI in 2007 than 2009. FluTracking data are consistent with NSW mortality data for influenza and pneumonia. Although laboratory data and emergency department (ED) data showed higher peak levels of influenza in 2009 then 2007, FluTracking found that the laboratory data were biased by increased testing in 2009 and ED data were biased by increased health seeking behaviour during the pandemic. See: http://wwwnc.cdc.gov/eid/article/16/12/10-0935-f1.htm

    Sentinel General Practice Surveillance


    The sentinel general practice ILI surveillance data between 2008 and 2012 consists of two main general practitioner schemes, the Australian Sentinel Practices Research Network (ASPREN) and a Victorian Infectious Disease Reference Laboratory (VIDRL) coordinated sentinel GP ILI surveillance program. Additionally, between 2008 and 2009 a Northern Territory surveillance scheme also operated, however this scheme has since been incorporated in to the ASPREN scheme. The national case definition for ILI is presentation with fever, cough and fatigue.

    The ASPREN currently has sentinel GPs who report ILI presentation rates in NSW, NT, SA, ACT, VIC, QLD, TAS and WA. The VIDRL scheme operates in metropolitan and rural general practice sentinel sites throughout Victoria and also incorporates ILI presentation data from the Melbourne Medical Deputising Service. As jurisdictions joined ASPREN at different times and the number of GPs reporting has changed over time, the representativeness of sentinel general practice ILI surveillance data in 2012 may be different from that of previous years.

    ASPREN ILI surveillance data are provided to the Department on a weekly basis throughout the year, whereas data from the VIDRL coordinated sentinel GP ILI surveillance program is provided between May and October each year.

    Approximately 30% of all ILI patients presenting to ASPREN sentinel GPs are swabbed for laboratory testing. Please note the results of ASPREN ILI laboratory respiratory viral tests now include Western Australia.

    Further information on ASPREN is available at www.dmac.adelaide.edu.au/aspren and information regarding the VIDRL coordinated sentinel GP ILI surveillance program is available at: https://www.victorianflusurveillance.com.au/.

    Sentinel Emergency Department Data

    Top of Page
    Western Australia – Emergency Department ILI surveillance data are extracted from the ‘Virus Watch’ Report. This report is produced weekly. The Western Australia Influenza Surveillance Program collects data from eight Perth emergency departments.
    New South Wales – Emergency Department ILI surveillance data are extracted from the ‘Weekly Influenza Report, NSW’. The New South Wales Influenza Surveillance Program collects data from 56 emergency departments across New South Wales.
    Northern Territory – this sentinel program collects data from the following hospitals: Royal Darwin, Gove District, Katherine District, Tennant Creek and Alice Springs. The definition of ILI is presentation to ED in the NT with one of the following presentations: febrile illness, cough, respiratory infection, or viral illness.

    National Notifiable Diseases Surveillance System (NNDSS)


    Laboratory confirmed influenza (all types) is notifiable under public health legislation in all jurisdictions in Australia. Confirmed cases of influenza are notified through the NNDSS by all jurisdictions. The national case definition is available at: http://www.health.gov.au/internet/main/publishing.nsf/Content/cda-surveil-nndss-casedefs-cd_flu.htm.

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

    Sentinel Laboratory Surveillance data


    Laboratory testing data are provided weekly directly from PathWest (WA), VIDRL (VIC), ICPMR (NSW), and Tasmanian laboratories reporting PCR results. Additionally, approximately 30% of all ILI patients presenting to ASPREN based sentinel GPs are swabbed for laboratory testing. Please note the results of ASPREN ILI laboratory respiratory viral tests now include Western Australia.

    Influenza Complications Alert Network (FluCAN)


    The Influenza Complications Alert Network (FluCAN) sentinel hospital system monitors influenza hospitalisations at the following sites:
    • Australian Capital Territory – the Canberra Hospital and Calvary Hospital;
    • New South Wales – John Hunter Hospital and Westmead Hospital;
    • Northern Territory – Alice Springs Hospital;
    • Queensland – the Mater Hospital, Princess Alexandria Hospital and Cairns Base Hospital;
    • South Australia – Royal Adelaide Hospital;
    • Tasmania – Royal Hobart Hosptial;
    • Victoria – Geelong Hospital, Royal Melbourne Hospital, Monash Medical Centre and Alfred Hospital;
    • Western Australia – Royal Perth Hospital.
    Influenza counts are based on active surveillance at each site for admissions with PCR-confirmed influenza in adults. Some adjustments may be made in previous periods as test results become available. ICU status is as determined at the time of admission and does not include patients subsequently transferred to ICU.

    Queensland Public Hospital Admissions (EpiLog)


    EpiLog is a web based application developed by Queensland Health. This surveillance system generates admission records for confirmed influenza cases through interfaces with the inpatient information and public laboratory databases. Records are also able to be generated manually. Admissions data reported are based on date of reported onset.

    Deaths associated with influenza and pneumonia

    Top of Page
    Nationally reported influenza associated deaths are notified by jurisdictions to the NNDSS, which is maintained by the Department of Health and Ageing. Notifications of influenza associated deaths are likely to underestimate the true number of influenza associated deaths occurring in the community.

    NSW influenza and pneumonia deaths data are collected from the NSW Registry of Births, Deaths and Marriages. Figure 16 is extracted from the ‘Weekly Influenza Report, NSW’. NSW Registered Death Certificates are routinely reviewed for deaths attributed to pneumonia or influenza. While pneumonia has many causes, a well-known indicator of seasonal and pandemic influenza activity is an increase in the number of death certificates that mention pneumonia or influenza as a cause of death. The predicted seasonal baseline estimates the predicted rate of influenza or pneumonia deaths in the absence of influenza epidemics. If deaths exceed the epidemic threshold, then it may be an indication that influenza is beginning to circulate widely.

    WHO Collaborating Centre for Reference & Research on Influenza


    Data on Australian influenza viruses are provided weekly to the Department from the WHO Collaborating Centre for Reference & Research on Influenza based in Melbourne, Australia.

    7. References

    Top of Page
    1. FluTracking Weekly Interim Report #6, 10 June 2012. Available from: http://www1.hnehealth.nsw.gov.au/hneph/HNEPHApplications/FluSurvey/Reports/LatestReport.pdf. Accessed 15 June 2012.
    2. The 2012 Victorian Influenza Vaccine Effectiveness Audit Report #6, 10 June 2012. Available from: www.victorianflusurveillance.com.au. Accessed 15 June 2012.
    3. WA Virus Watch Report, 10 June 2012. Available from: http://www.public.health.wa.gov.au/cproot/4604/2/20120610_virus_watch.pdf. Accessed 15 June 2012.
    4. NSW Influenza Weekly Epidemiology Report, 2 to 8 June 2012. Available from: http://www.health.nsw.gov.au/resources/publichealth/infectious/influenza/pdf/weekending_08062012l.pdf. Accessed 15 June 2012.
    5. WHO Recommended composition of influenza virus vaccines for use in the 2012-13 northern hemisphere influenza season. Available from: http://www.who.int/influenza/vaccines/virus/recommendations/2012_13_north/en/index.html. Accessed 15 June 2012.
    6. WHO Influenza Update 161 (8 June 2012). Available from: http://www.who.int/influenza/surveillance_monitoring/updates/latest_update_GIP_surveillance/en/index.html#. Accessed 15 June 2012.
    7. New Zealand Influenza Weekly Update, 4 to 10 June 2012. Available from: http://www.surv.esr.cri.nz/virology/influenza_weekly_update.php, Accessed 15 June 2012.
    8. WHO Laboratory confirmed data from the Global Influenza Surveillance Network – 8 June 2012. Available from: http://www.who.int/influenza/gisrs_laboratory/updates/summaryreport/en/index.html. Accessed 15 June 2012.