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 42,246 laboratory confirmed notifications of Influenza in Australia for 2016, at the end of 28th August.

•    QLD:   12,135
•    NSW:  18,011
•    WA:      3,718 
•    SA:       2,111
•    VIC:      4,916
•    ACT:        783
•    NT:           218
•    TAS:         354

For more national data:  

National Notifiable Diseases Surveillance System

Australian Influenza Surveillance Report                                                             

New South Wales

21 August 2016

Seasonal influenza activity continues to rise steadily and is currently following a similar course to last year (2015). The season is likely to be at or near its peak activity.

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

Hospital Surveillance – the rate of influenza like illness (ILI) presentations to selected emergency departments increased and remains well above the seasonal threshold.

Laboratory surveillance – the total number of influenza isolations continues to rise along with the proportion of respiratory samples positive for influenza (30.1%).

Community surveillance – influenza notifications were increased across most local health districts (LHD). General Practice and community-based surveillance systems suggest increased 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 indicating that the season is underway. Current influenza strains are well matched to the 2016 influenza vaccines. Influenza activity is increasing in some other regions in the Southern Hemisphere.

For more information: NSW Health - Infectious Diseases Alert

Queensland

21 August 2016

Recent week onset (15 to 21 August) there were 1,293 notifications.
1,262 (98%) were typed as influenza A and 31 (2%) influenza B 

80 influenza A have been subtyped: 11 (14%) were A(H1N1)pdm09 and 69 (86%) were A/H3N2 

Subtype is unavailable for 1,182 influenza A cases. 

YTD 2016 (1 January to 21 August) there have been 10,573 notifications.

Influenza A:  9,655 (91%)

Influenza B:  918 (9%) 

1,417 influenza A have been subtyped:  648 (46%) were A(H1N1)pdm09 and 769 (54%) were A/H3N2 

Subtype is unavailable for 8,238 influenza A cases. 

The 2016 season has been underway for several weeks. Although the season peak cannot be accurately predicted the current pattern suggests this is likely to occur within the next few weeks.

The statewide percentage of positive tests in the most recent week was 15.7%
Percentage positive for the southern, central and tropical regions in the most recent week was recorded as 18.3%, 13.2% and 11.0% respectively.

Only a small percentage of flu A (15%) and flu B (3%) have been further characterised. Data from the World Health Organization Collaborative Centre for Reference and Research on Influenza (WHO CC) indicate that the circulating strains are covered by the 2016 quadrivalent vaccine.

For more information: QLD Health - Preventable Diseases                                                                                                                                                                                                                                                                                                                                                                                                             

South Australia

13 August 2016

One hundred and sixty-eight cases of influenza were reported this week with 152 cases being characterised as influenza A and 16 as influenza B. Cases comprised of 81 males and 87 females, with a median age of 38 years. Thirty-four (20%) notifications were for children aged less than 10 years and 34 (20%) notifications for persons aged 65 years or greater. There have been 1,527 cases of influenza notified year-to-date, compared with 6,601 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

21 August 2016

Measures of influenza-like illness (ILI) from VicSPIN indicate the season is currently at average levels. The ILI rate from the National Home Doctor Service remained above baseline levels in the last week.

The number of notified laboratory confirmed influenza cases for the year to 21 August is 55% lower than the same time in 2015. Of the notified influenza cases, 89% have been type A. VicSPIN detected eight positive influenza A(H3N2), one influenza B and three influenza(untyped) during the week.

Overall the data from the influenza and ILI surveillance systems indicate the influenza season is slightly above baseline levels in Victoria.

For more information: Victorian Infectious Diseases Reference Laboratory

Western Australia

21 August 2016

ILI activity has stabilised this week, but influenza notifications continue to increase, with influenza A/H3N2 the dominant circulating strain.

ILI presentations to sentinel general practitioners (GPs) and emergency departments (EDs) stabilised this week but remain relatively high.

The percent of tests positive for influenza virus and notifications of laboratory-confirmed influenza remain higher than levels experienced at the corresponding time in the past three years.

Hospital admissions with notified influenza (primarily due to A/H3N2 virus) appear to be still increasing and are above the recent average for this time of year.

Influenza A/H3 (69% of detections) is still the dominant circulating virus, along with influenza B (25%).

Several influenza (A/H3N2) outbreaks have been reported in residential aged care facilities in the past few weeks.

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.

17 July 2016

Influenza-like-illness levels increased remaining above baseline 

Nationally, ILI notifications increased over the period with 129 and 155 notifications in weeks 27 and 28 respectively. ILI rates reported in this period were slightly higher with 8 and 9 cases weighted / 7 cases unweighted per 1000 consultations in weeks 27 and 28 respectively, compared to 7 and 8 cases weighted / 6 unweighted per 1000 consultations in weeks 25 and 26 respectively. For the same reporting period in 2015, ILI rates were slightly higher at 10 cases weighted / 9 unweighted per 1000 consultations. On a state -by-state basis, it is important to note the increased ILI rate in Remote NSW.

(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.

21 August 2016

Moderate levels of influenza-like illness activity

This survey was sent on Monday, 22 August 2016 at 01:13 AM and by 09:00 AM, Thursday 25 August we had received 23075 responses (23206 last week) from 13930 people responding for themselves and 9145 household members across Australia.

Across Australia, fever and cough was reported by 2.3% of vaccinated participants and 3.1% of unvaccinated participants. Fever, cough and absence from normal duties was reported by 1.8% of vaccinated participants and 2.3% of unvaccinated participants.

For participants this week, 13990/23075 (60.6 %) have received the seasonal vaccine so far. Of the 4518 participants who identified as working face-to-face with patients, 3631 (80.4%) have received the vaccine.

For more information, or to enrol: Flu Tracking

New Zealand

21 August 2016

During week 33 (15–21 August 2016), influenza activity was very low among consultation-seeking patients nationwide. Influenza activity was also very low among those hospitalised patients in Auckland and Counties Manukau District Health Boards.

One hundred and seventeen patients with influenza-like illness consulted sentinel general practices in 20 DHBs. The weekly ILI incidence was 22.2 per 100 000 patient population, below the seasonal threshold of ILI consultations. The ILI related influenza incidence (adjusted) was 10.2 per 100 000 patient population.

During this week, 48 ILI specimens were tested, 22 were positive for influenza viruses.

For more information:  NZ Flu Surveillance