Report No. 2
Week ending 22 June 2012

PDF printable version of Australian Influenza Surveillance Report No 2 - 2012 (PDF 1618 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

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• Across all surveillance systems, influenza activity has continued to increase this fortnight.
• All jurisdictions have reported increases in influenza detections above background levels, with South Australia, Victoria, New South Wales, the Australian Capital Territory and the centre of the Northern Territory reporting significant recent increases in activity.
• Influenza-like illness (ILI) activity has continued to increase, with the seasonal increase occurring slightly earlier than in previous years (excluding 2009).
• During this fortnight there were 2,233 laboratory confirmed notifications of influenza, almost double the number of notifications from the previous fortnight. New South Wales, Queensland and South Australia continue to report the highest number of notifications.
• Nationally, influenza A(H3N2) is the predominant circulating strain with some co-circulation of influenza B. Influenza A(H3N2) is predominant across most states and territories, however influenza B represents around 75% and 40% 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 22 June 2012, there have been 6,027 confirmed cases of influenza reported. Excluding 2009, notifications of influenza in 2012 have started their seasonal increase slightly earlier in comparison with previous years.
• Influenza associated hospitalisations have continued to increase this fortnight, particularly at the South Australian and Northern Territory sites. Overall, 40% of hospitalisations have been associated with influenza B infections, mostly reported from the Northern Territory. Amongst other jurisdictional sites, influenza A is more common.
• The WHO has reported that the influenza season has not yet started in the temperate countries of the southern hemisphere, although several countries, including Australia, Chile, Paraguay and South Africa have reported small but sustained increases of influenza virus detections. Influenza A(H3N2) viruses have been the most commonly detected in recent weeks in the southern hemisphere temperate region.

1. Geographic Spread of Influenza Activity in Australia

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In the fortnight ending 22 June 2012, the geographic spread of influenza activity reported by state and territory Health Departments was ‘sporadic’ in northern Queensland; ‘localised’ in the top end of the Northern Territory, central Queensland, Tasmania and Western Australia; ‘regional’ in southern Queensland; and ‘widespread’ in the ACT, New South Wales, South Australia and the centre of the NT (figure 1). During this period, New South Wales, Victoria, Tasmania and Western Australia 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 22 June 2012

2. Influenza-like illness activity

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Community Level Surveillance

FluTracking

FluTracking, a national online system for collecting data on ILI in the community, noted that in the week ending 24 June 2012 fever and cough was reported by 3.1% of vaccinated participants and 4.5% of unvaccinated participants (figure 2). FluTracking Weekly Interim Report #6, 10 June 2012. Available from Flu Tracking (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 1.8% of vaccinated participants and 2.6% of unvaccinated participants. Current rates of ILI among FluTracking participants are relatively consistent with previous years (figure 3).

Up to 24 June 2012, 52.2% of participants reported having received the seasonal vaccine so far. Of the 2,392 participants who identified as working face-to-face with patients, 72.3% 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 24 June 2012

Figure 3. Proportion of fever and cough among FluTracking participants by week, between May and October, 2008 to 2012

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National Health Call Centre Network

The number of ILI related calls to the National Health Call Centre Network (NHCCN) continued to increase this fortnight. In the week ending 24 June 2012, the proportion of total calls which were ILI related increased to 10.9%, which is slightly higher than the peak proportions of calls experienced in 2010 and 2011(figure 4).

Figure 4. Number of calls to the NHCCN related to ILI and percentage of total calls, Australia, 1 January 2010 to 24 June 2012

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Sentinel General Practice Surveillance

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In the week ending 24 June 2012, sentinel general practitioner ILI consultation rates were relatively consistent with the previous fortnight at 13.6 cases per 1,000 consultations (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 24 June 2012*

* 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.
In the fortnight ending 24 June 2012, specimens were collected from almost half of ASPREN ILI patients. Of these patients, 32% were positive for influenza, up from 28% in the previous fortnight. Nineteen percent were positive for influenza type A, with the majority likely to be attributed to A (H3N2); and the remaining 13% were influenza type B (figure 6 and table 1). Just over twenty percent of specimens collected were positive for other respiratory viruses this fortnight, with the majority of these being either rhinovirus or RSV.

Table 1. ASPREN laboratory respiratory viral test results of ILI consultations, 1 January 2012 to 24 June 2012.

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	Fortnight (11 June – 24 June 2012)	YTD (1 January – 24 June 2012)
Total specimens tested	186	868
Total Influenza Positive (%)	31.7	21.2
Influenza A (%)	18.8	14.1
Pandemic (H1N1) 2009 (%)	0.0	0.2
Influenza A (unsubtyped) (%) #	18.8	13.8
Influenza B (%)	12.9	7.1
Other Resp. Viruses (%)*	21.5	28.3

^# 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 24 June 2012

Sentinel Emergency Department Surveillance

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Western Australia Emergency Departments

In the fortnight ending 24 June 2012, respiratory viral presentations to WA emergency departments continued to increase steadily and are higher than in recent years (figure 7). Over this period there were 1,320 presentations, including 70 admissions. The proportion of presentations requiring admission to hospital over this period remained stable at 5.3%.

Figure 7. Number of respiratory viral presentations to Western Australia emergency departments from 1 January 2008 to 24 June 2012, by week

New South Wales Emergency Departments

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In the week ending 22 June 2012 the number of patients presenting to NSW emergency departments with ILI eased slightly, but still remains above the usual range for this time of year (figure 8). Activity for respiratory illness in people aged 65 years or older was at or above peak levels in a range of emergency department categories. Total admissions from emergency departments to critical care units for ILI and pneumonia decreased this week, and have returned to the usual range for this time of year. NSW Influenza Weekly Epidemiology Report, 16 to 22 June 2012. Available from NSW Health (www.health.nsw.gov.au/resources/publichealth/infectious/influenza/pdf/weekending_22062012l.pdf). Accessed 2 July 2012.

Figure 8. Rate of influenza-like illness presentations to New South Wales emergency departments, between May and October, 2008 to 2012, by week*

Northern Territory Emergency Departments

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In the fortnight ending 16 June 2012, the number of patients presenting with ILI to emergency departments across the Northern Territory was 507, which is slightly above the number of presentations observed in previous years over the same period (excluding 2009) (figure 9).

Figure 9. Number of ILI presentations to Northern Territory emergency departments, 1 January 2008 to 16 June 2012, by week

3. Laboratory confirmed influenza activity

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Notifications of Influenza to Health Departments

During the reporting period there were 2,233 laboratory confirmed influenza notifications reported to the NNDSS, almost double the number of notifications from the previous fortnight. Of these notifications, 833 were in NSW, 512 in Queensland, 429 in SA, 228 in Victoria, 143 in WA, 38 in the ACT, 29 in the NT and 21 in Tasmania (figure 10). A weekly breakdown of trends by state and territory highlights that notifications are continuing to increase across all states and territories and are highest in New South Wales, Queensland and South Australia (figure 11).

Figure 10. Laboratory confirmed cases of influenza in Australia, 1 January to 22 June 2012, by state, by week.

Figure 11. State breakdowns of laboratory confirmed cases of influenza, 1 January to 22 June 2012, by week

Top of pageUp to 22 June, there have been 6,027 laboratory confirmed notifications of influenza diagnosed during 2012 (figure 12). Of these notifications, there have been 1,789 in New South Wales, 1,617 in Queensland, 915 in South Australia, 730 in Victoria, 706 in Western Australia, 147 in the Northern Territory, 81 in the ACT and 42 in Tasmania.

Figure 12. Laboratory confirmed cases of influenza in Australia, 1 January 2008 to 22 June 2012

Top of pageOf the 2,233 influenza notifications reported to the NNDSS this reporting period, 1,910 were influenza A (1,447 were influenza A (unsubtyped), 446 were A(H3N2) and 17 were pandemic (H1N1) 2009), 317 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 almost 75% and 40% 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, 4,731 (78%) cases were reported as influenza A (57% influenza A (unsubtyped), 20% A(H3N2) and 1% pandemic (H1N1) 2009) and 1,263 (21%) were influenza B. A further 23 (<1%) were influenza type A&B and 10 (<1%) were untyped (figure 13).

Figure 13. Laboratory confirmed cases of influenza in Australia, 1 January to 22 June 2012, by sub-type and week

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Sentinel Laboratory Surveillance

Results from sentinel laboratory surveillance systems for this reporting period show that 18.3% of the respiratory viral tests conducted over this period were positive for influenza, an increase from 8.0% in the previous fortnight (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, 9 June to 22 June 2012

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	NSW NIC	WA NIC	VIC NIC	TAS (PCR Testing Data)
Total specimens tested	443	552	250	106
Total Influenza Positive	104	86	39	17
Positive Influenza A	98	48	34	15
Pandemic (H1N1) 2009	0	1	2	0
A(H3N2)	82	47	30	11
Influenza A unsubtyped	16	0	2	4
Positive Influenza B	6	38	5	2
Proportion Influenza Positive (%)	23.5	15.6	15.6	16.0
Most common respiratory virus detected	Influenza A	Influenza A(H3N2)	Picornavirus	Influenza A(H3N2)

Figure 14. Proportion of sentinel laboratory tests positive for influenza, by subtype and fortnight, 26 May to 22 June 2012

Hospitalisations

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Influenza Complications Alert Network (FluCAN)

The Influenza Complications Alert Network (FluCAN) sentinel hospital surveillance system has reported that there has been an increased number of admissions with confirmed influenza in the last fortnight, particularly from the South Australian and Northern Territory sites. Since 7 April 2012, eight percent of influenza patients have been admitted directly to ICU. Overall, 40% of cases have been due to influenza B (figure 15), however most of these presentations are from the Northern Territory, with influenza A more common in other states. Around half of the cases are aged 65 years and over (median age 47 years) and almost 70% of all cases have known medical co-morbidities.

Figure 15. Number of influenza hospitalisations at sentinel hospitals, by week and influenza subtype, 7 April to 22 June 2012

Queensland Public Hospital Admissions (EpiLog)

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Admissions to public hospitals in Queensland of confirmed influenza are detected through the EpiLog system. In the fortnight ending 24 June 2012, the number of admissions of confirmed admissions associated with confirmed influenza continued to increase and accounted for over a quarter of the total admissions so far in 2012 (42/154) (figure 16). The median age of hospitalisations was 27 years (range <1 to 102 years), with a bimodal distribution peaking mostly in the 0-9 year age group and also in the 70-79 year age group.

Figure 16. Number of influenza admissions to Queensland public hospitals, by week and type of admission, with onset from 1 January to 24 June 2012

Deaths associated with influenza and pneumonia

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Nationally Notified Influenza Associated Deaths

So far in 2012, 7 influenza associated deaths have been notified to the NNDSS, with a median age of 75 years (range 51 to 81 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 for the week ending 1 June 2012 showed that there were 1.4 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).

Figure 17. Rate of deaths classified as influenza and pneumonia from the NSW Registered Death Certificates, 1 January 2007 to 1 June 2012

4. Virological Surveillance

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Typing and antigenic characterisation

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

From 1 January to 25 June 2012, there were 327 Australian influenza viruses subtyped by the WHO CC with a relatively equal split between viruses subtyped as influenza A(H3N2) and influenza B. So far this year, very few viruses have been 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 25 June 2012

Type/Subtype	ACT	NSW	NT	QLD	SA	TAS	VIC	WA	TOTAL
Pandemic (H1N1) 2009	0	0	1	2	1	0	6	5	15
A(H3N2)	0	36	1	45	30	3	34	12	161
B	0	8	37	27	17	3	23	36	151
Total	0	44	39	74	48	6	63	53	327

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 almost all 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 there is 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 24 June 2012, one influenza virus (out of 246 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:

• an A/California/7/2009 (H1N1)pdm09-like virus;
• an A/Victoria/361/2011 (H3N2)-like virus;
• a B/Wisconsin/1/2010-like virus WHO Recommended composition of influenza virus vaccines for use in the 2012-13 northern hemisphere influenza season. Available from WHO (who.int/influenza/vaccines/virus/recommendations/2012_13_north/en/index.html). Accessed 15 June 2012.

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 that:

• 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

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The WHO WHO Influenza Update 162 (22 June 2012). Available from WHO (www.who.int/influenza/surveillance_monitoring/updates/2012_06_22_surveilance_update_162.pdf). Accessed 2 July 2012. has reported that as at 22 June 2012 the influenza season is largely finished in the temperate countries of the northern hemisphere, with some persistent low level influenza transmission in eastern Europe and northern China. The influenza season has not yet started in the temperate countries of the southern hemisphere, although several countries, including Australia, Chile, Paraguay and South Africa have reported small but sustained increases of influenza virus detections. Influenza A(H3N2) viruses have been the most commonly detected in recent weeks in the southern hemisphere temperate region. A detailed review of the recent northern hemisphere season is available at WHO (www.who.int/wer/2012/wer8724/en/).

In New Zealand New Zealand Influenza Weekly Update, 18 to 24 June 2012. Available from Surveillance NZ (www.surv.esr.cri.nz/PDF_surveillance/Virology/FluWeekRpt/2012/FluWeekRpt201225.pdf). Accessed 2 July 2012. , for the week ending 24 June 2012, the national rate of ILI consultations continue to be below the baseline level of activity, however, 6 of the twenty district health boards were above the national average weekly consultation rate of 19.6 per 100,000. Virological surveillance through both sentinel and non-sentinel laboratories shows that so far this year 41% have been influenza A(H3N2) viruses, 28% influenza B viruses and 16% were pandemic (H1N1) 2009 virus detections, with the remainder being influenza A (unsubtyped). The majority of circulating influenza strains are noted as being covered by the 2012 southern hemisphere vaccine.

National Influenza Centres and laboratories in 79 countries, areas or territories, have reported that for the period 27 May to 9 June 2012, a total of 1,959 specimens were reported as positive for influenza viruses, with 76% being influenza A and 22% influenza B. Of the sub-typed influenza A viruses, 89% were influenza A(H3N2) and 11% were pandemic (H1N1) 2009 WHO Laboratory confirmed data from the Global Influenza Surveillance Network – 22 June 2012. Available from WHO (http://www.who.int/influenza/gisrs_laboratory/updates/summaryreport/en/index.html#). Accessed 2 July 2012. Of the characterised influenza B viruses, 50% belong to the B/Yamagata lineage and 50% to the B/Victoria lineage.

6. Data considerations

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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 level	Laboratory notifications		Influenza outbreaks
Sporadic	Small no of lab confirmed influenza detections (not above expected background level)+	AND	No outbreaks
Localised	Recent increase in lab confirmed influenza detections above background level ++ in less than 50% of the influenza surveillance regions** within the state or area	OR	Single outbreak only
Regional	Significant*** 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 area	OR	> 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

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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).

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 Victorian Flu Surveillance (www.victorianflusurveillance.com.au/).

Sentinel Emergency Department Data

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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 CDA Surveillance (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.

Influenza Complications Alert Network (FluCAN)

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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 Hospital;
• 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

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

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1. FluTracking Weekly Interim Report #6, 10 June 2012. Available from HNEP (www1.hnehealth.nsw.gov.au/hneph/HNEPHApplications/FluSurvey/Reports/LatestReport.pdf). Accessed 15 June 2012.
2. The 2012 Victorian Influenza Vaccine Effectiveness Audit Report #8, 2 June 2012. Available from Victorian Flu Surveillance (www.victorianflusurveillance.com.au). Accessed 2 July 2012.
3. WA Virus Watch Report, 24 June 2012. Available from WA Health (www.public.health.wa.gov.au/cproot/4604/2/20120624_virus_watch.pdf). Accessed 2 July 2012.
4. NSW Influenza Weekly Epidemiology Report, 16 to 22 June 2012. Available from NSW Health (www.health.nsw.gov.au/resources/publichealth/infectious/influenza/pdf/weekending_22062012l.pdf). Accessed 2 July 2012.
5. WHO Recommended composition of influenza virus vaccines for use in the 2012-13 northern hemisphere influenza season. Available from WHO(www.who.int/influenza/vaccines/virus/recommendations/2012_13_north/en/index.html). Accessed 15 June 2012.
6. WHO Influenza Update 162 (22 June 2012). Available from WHO (www.who.int/influenza/surveillance_monitoring/updates/2012_06_22_surveilance_update_162.pdf). Accessed 2 July 2012.
7. New Zealand Influenza Weekly Update, 18 to 24 June 2012. Available from NZ Surveillance (www.surv.esr.cri.nz/PDF_surveillance/Virology/FluWeekRpt/2012/FluWeekRpt201225.pdf). Accessed 2 July 2012.
8. WHO Laboratory confirmed data from the Global Influenza Surveillance Network – 22 June 2012. Available from WHO (www.who.int/influenza/gisrs_laboratory/updates/summaryreport/en/index.html#). Accessed 2 July 2012.Top of page

   In this section

   • Australian influenza report—2012