Influenza Activity Surveillance

Surveillance of Influenza activity in Australia & New Zealand

This report provides a summary of surveillance data collected from around Australia and New Zealand. Regional reporting in some areas ceases when flu activity is low (out of season).

Please note that the vast majority of people do not get tested for influenza and that there may also be some delays in reporting confirmed influenza cases. Therefore data presented here maybe underestimating influenza activity.

Australia

Commonwealth Department of Health & Ageing

There have been a total of 69,808 laboratory confirmed notifications of Influenza in Australia for 2016, at the end of 25th September.

•    QLD:   18,229
•    NSW:  30,041
•    WA:       6,121 
•    SA:        3,960
•    VIC:       8,880
•    ACT:      1,418
•    NT:            369
•    TAS:          790

For more national data:  

National Notifiable Diseases Surveillance System

Australian Influenza Surveillance Report                                                             

New South Wales

18 September 2016

Seasonal influenza activity continues to fall overall but remains high in some areas, particularly the Hunter New England Local Health District.

Influenza A(H3N2) remains the dominant circulating influenza strain.

In this reporting week:

Hospital Surveillance – influenza like illness (ILI) presentations to selected emergency departments decreased and were below peak levels. The index of increase indicates that activity peaked on 28 August 2016.

Laboratory surveillance – the total number of influenza isolations decreased further this week with the proportion of respiratory samples positive for influenza at 21.0%.

Community surveillance – influenza notifications continued to be high across most local health districts (LHD), but decreasing. General Practice and community-based surveillance systems showed decreasing ILI activity. Influenza activity continues to impact heavily on the aged care sector with 22 new respiratory outbreaks reported this week in residential aged care facilities.

National and international influenza surveillance – the most recent national reports suggest influenza activity at the national level continued to increase, with most regions of Australia reporting widespread and increasing activity. Current influenza strains are well matched to the 2016 influenza vaccines.

For more information: NSW Health - Infectious Diseases Alert

Queensland

18 September 2016

Recent week onset (12 to 18 September) there were 1,210 notifications. 

1,165 (96%) were typed as influenza A and 45 (4%) influenza B. 

76 influenza A have been subtyped: six (8%) were A(H1N1)pdm09 and 70 (92%) were A/H3N2.

Subtype is unavailable for 1,089 influenza A cases. 

YTD 2016 (1 January to 18 September) there have been 17,325 notifications. 16,174 (93%) were typed as influenza A and 1,151 (7%) influenza B 

2,104 influenza A have been subtyped: 729 (35%) were A(H1N1)pdm09 and 1,375 (65%) were A/H3N2. 

Subtype is unavailable for 14,070 influenza A cases. 

The current pattern is consistent with the Queensland season nearing its peak, although there are regional variations.

The statewide percentage of positive tests in the most recent week was 17.9%, which is consistent with continued transmission within the community. Care should be taken not to over interpret the difference in notification counts between weeks 35 and 36.

Notification counts and percentage positive for the recent week may change as further data become available and will be adjusted in the next report. The apparent downward trend would need to be sustained over several weeks to suggest that activity in the community is decreasing. 

Percentage positive for the southern, central and tropical regions in the most recent week was recorded as 22.7%, 17.6% and 21.0% respectively.

YTD notification count in males was 8% lower than in females.
Median age was 42 years, with a range of younger than one year to 104 years.

For more information: QLD Health - Preventable Diseases                                                                                                                                                                                                                                                                                                                                                                                                             

South Australia

10 September 2016

Four hundred and twenty-six cases of influenza were reported this week with 405 cases being characterised as influenza A and 21 as influenza B. Cases comprised of 200 males and 226 females, with a median age of 35 years. Eighty-nine (21%) notifications were for children aged less than 10 years and 74 (17%) notifications for persons aged 65 years or greater. There have been 3,059 cases of influenza notified year-to-date, compared with 11,800 cases reported for the same period last year.

For more information: Communicable Diseases Control Branch

Tasmania

18 August 2016

This report describes influenza activity in Tasmania during July 2016. 

The modest increase in influenza activity at the end of July is similar to pre-season activity observed in recent years.

The 2016 winter flu season appeared to be beginning toward the end of July.

Influenza A virus is the most common cause of laboratory confirmed Influenza. The most common circulating strains included A(H1N1)pdm09, followed by A(H3N2). The 2016 annual vaccine covers these strains.

There was a small increase in laboratory tests of nose and throat swabs during July. Respiratory Syncytial Virus (RSV) was the most commonly detected respiratory pathogen followed by Rhinovirus and Influenza A virus.

Surveillance of influenza-like illness by General Practice and FluTracking continued to indicate low activity
during this period.

There were a further 37 notifications of influenza during July, resulting in a total of 159 influenza notifications since the start of 2016. The July total of 37 notifications is the largest monthly total since the start of 2016. Weekly notification counts increased during July, with 18 of the 37 influenza notifications in the final week.
During July 2016, Influenza A virus was the most common cause of influenza in Tasmania: isolated in 34 out of 37 notifications. Since the start of 2016, additional laboratory typing has been performed on 25 samples of influenza A virus. Sixteen samples were the A(H1N1)pdm09 strain while the remaining nine were A(H3N2).

There have been no outbreaks of influenza in a residential institution reported since the start of 2016. 

Since the start of 2016, 55 per cent of influenza was diagnosed by PCR (nose and throat swabs). The remaining cases were diagnosed by a blood test (serology). 

During July there was an average of 98 weekly PCR tests performed. This was an increase in testing compared with the January to May period (average 52 per week). The proportion of tests positive for influenza increased from one per cent to 12 per cent during July 2016. In past years the proportion of weekly tests typically increased above 10 per cent during the early weeks of Tasmanian (winter) influenza seasons.

For more information: Communicable Diseases Prevention - FluTAS

Victoria

18 September 2016

Influenza-like illness (ILI) surveillance indicates the season is still at average levels.

The number of notified laboratory confirmed influenza cases for the year to 18 September is 48% lower than at the same time in 2015. Of the notified influenza cases, 92% have been type A. Forty-four percent of VicSPIN swabs were positive for influenza, most of which were influenza A(H3N2).

Influenza and ILI surveillance systems are indicating that the 2016 season peaked between late August and early September.

For more information: Victorian Infectious Diseases Reference Laboratory

Western Australia

18 September 2016

Indicators of ILI and influenza activity suggest the influenza season reached its peak in late August, but activity remains high, with influenza A/H3N2 virus as the dominant circulating strain.

ILI presentations to sentinel general practitioners (GPs) remain higher than expected, possibly due to increased training and recruitment of sentinel GPs.

ILI presentations to sentinel emergency departments (EDs) have plateaued over the past few weeks, but remain relatively high.

The percent of tests positive for influenza virus and notifications of laboratory-confirmed influenza decreased this week but remain in the higher range of values observed during this time period in recent years.

Hospital admissions with notified influenza have plateaued over recent weeks but remain above the average level experienced in recent years.

Influenza A/H3N2 (74% of detections) remains the dominant circulating virus with continuing influenza B (24%) activity.

One new influenza outbreak was reported in a residential aged care facility in the past week, with over 30 outbreaks reported so far this season.

For more information: WA Virus WAtch

Nationally

Australian Sentinel Practices Research Network (ASPREN)

ASPREN is a national syndromic surveillance program co-ordinated by the Discipline of General Practice at the University of Adelaide and The Royal Australian College of General Practitioners. One of the conditions under surveillance is influenza like illness (ILI). General practitioners participating in the ASPREN program contribute data on the proportion of consultations which are ILI related.

14 August 2016

Influenza-like-illness levels increased remaining above baseline. 

85 Cases of influenza have been detected in this reporting period:
75 x Influenza A and 10 x Influenza B.

37% Influenza positivity during the reporting period. 

204 Cases of influenza have been detected this year: 152x Influenza A
52 x Influenza B 

Reports were received from 293 GPs from 8 states and territories during the reporting period. During weeks 31 and 32 a total of 21,960 and 21,025 consultations were made respectively. 

Nationally, ILI notifications increased over the period with 255 and 265 notifications in weeks 31 and 32 respectively. ILI rates reported in this period were higher with 13 cases weighted / 12 and 13 cases unweighted per 1000 consultations in weeks 31 and 32 respectively, compared to 11 and 10 cases weighted / 8 and 9 unweighted per 1000 consultations in weeks 29 and 30 respectively. For the same reporting period in 2015, ILI rates were the higher at 14 and 15 cases weighted / 14 unweighted per 1000 consultations. On a state-by-state basis, it is important to note the increased ILI rate in Urban ACT.

(Baseline ILL < 4 in 1000 consultations, Normal 4< ILL rate <24).

For more information: ASPREN 

Flu Tracking

FluTracking is a pilot online health surveillance system which aims to detect epidemics of influenza. It is a joint initiative of The University of Newcastle, Hunter New England Area Health Service (NSW Health) and Hunter Medical Research Institute. Participation is voluntary and involves the completion of a weekly online survey during the influenza season. Data are collected on basic demographics, symptoms of ILI and absenteeism.

18 September 2016

Low levels of influenza-like illness activity.

This survey was sent on Monday, 19 September 2016 at 01:13 AM and by 09:00 AM, Tuesday 20 September we had received 20127 responses (20402 last week) from 12264 people responding for themselves and 7863 household members across Australia.

Across Australia, fever and cough was reported by 2.1% of vaccinated participants and 2.3% of unvaccinated participants. Fever, cough and absence from normal duties was reported by 1.6% of vaccinated participants and 1.7% of unvaccinated participants. 

For participants this week, 12299/20127 (61.1 %) have received the seasonal vaccine so far. Of the 3833 participants who identified as working face-to-face with patients, 3101 (80.9%) have received the vaccine.

For more information, or to enrol: Flu Tracking

New Zealand

18 September 2016

During week 37 (12–18 September 2016), influenza activity was very low among consultation-seeking patients nationwide. Influenza activity was also low among those hospitalised patients in Auckland and Counties Manukau District Health Boards. 

Forty-eight patients with influenza-like illness consulted sentinel general practices in 20 DHBs. The weekly ILI incidence was 9.1 per 100 000 patient population, below the seasonal threshold of ILI consultations. The ILI related influenza incidence (adjusted) was 4.9 per 100 000 patient population.

During this week, 30 ILI specimens were tested, 16 were positive for influenza viruses.

For more information:  NZ Flu Surveillance