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 89,430 laboratory confirmed notifications of Influenza in Australia for 2016, at the start of 21st December.

•    QLD:   22,973
•    NSW:  35,238
•    WA:       7,775 
•    SA:        7,686
•    VIC:     12,464
•    ACT:      1,595
•    NT:           665
•    TAS:       1034

For more national data:  

National Notifiable Diseases Surveillance System

Australian Influenza Surveillance Report                                                             

New South Wales

November Report 2016

Influenza A and B strains are continuing to circulate at low inter-seasonal levels.

Influenza activity is likely to remain at low levels until the winter of 2017.

Hospital Surveillance

NSW emergency department (ED) surveillance for influenza-like illness (ILI) and other respiratory illnesses is conducted through PHREDSS.
The PHREDSS surveillance system uses a statistic called the ‘index of increase’ to indicate when ILI presentations are increasing at a statistically significant rate. It accumulates the difference between the previous day’s count of presentations and the average for that weekday over the previous 12 months. An index of increase value of 15 is a considered an important signal for the start of the influenza season in NSW as it suggests influenza is circulating widely in the community. 

Laboratory testing summary for influenza  In November 2016

656 specimens tested positive for influenza A – 88 tested positive for influenza A(H3N2),11 of these tested positive for A(H1N1) and 555 were not typed further. 

383 cases of influenza B were reported
The number of influenza-positive tests has declined throughout November. However, overall influenza activity remains slightly higher than usual for this time of year. Rhinoviruses were the leading respiratory viruses identified by laboratories. Other viruses are circulating at usual levels for this time of year.
Community Surveillance 

Influenza notifications by Local Health District (LHD) 

During November (5 week period) there were 1,112 notifications of influenza confirmed by polymerase chain reaction (PCR) testing, lower than the 2,087 influenza notifications reported for October 2016. Population rates were low and similar across all LHDs 

Influenza outbreaks in institutions 

There were three influenza A outbreaks reported this month in aged care facilities. All were due to influenza A. 

In the year to date there have been 275 laboratory confirmed influenza outbreaks in institutions reported to NSW public health units: 268 have been due to influenza A, five were influenza B, and three were combined influenza A and B outbreaks. At least 4,060 residents were reported to have had ILI symptoms and 468 required hospitalisation. One hundred and ninety one deaths in residents linked to these outbreaks have been reported, all of whom were noted to have other significant co-morbidities. 

People in older age-groups are at higher risk of infection from influenza A(H3N2) strains than from the influenza A(H1N1) strain. The influenza A(H3N2) strain predominated in 2012 and 2014. In 2015, influenza B was the predominant strain, and was also the cause of some influenza outbreaks in institutions, particularly residential aged care facilities

For more information: NSW Health - Infectious Diseases Alert

Queensland

9 October 2016

This is the final report for the 2016 influenza season. A more detailed report will be available in early 2017.

Recent week onset (3 to 9 October) there were 462 notifications.
424 (92%) were typed as influenza A and 38 (8%) influenza B 

27 influenza A have been subtyped: one (4%) were A(H1N1)pdm09 and 26 (96%) were A/H3N2 

Subtype is unavailable for 397 influenza A cases. 

YTD 2016 (1 January to 9 October) there have been 19,736 notifications.
18,442 (93%) were typed as influenza A and 1,294 (7%) influenza B 

2,534 influenza A have been subtyped: 786 (31%) were A(H1N1)pdm09 and 1,748 (69%) were A/H3N2 

Subtype is unavailable for 18,442 influenza A cases. 

The Queensland season reached its peak in week 35 (week beginning 22 August) with a total of 1,864 notifications and a percentage positive of 27.7
The statewide percentage of positive tests in the most recent week was 11.4, which is consistent with decreasing influenza activity since the season peak.
Notification counts and percentage positive for the recent week may change as further data become available.
The southern region experienced peaks in weeks 33 and 35 with 974 and 967 notifications, respectively.
The central region’s peak occurred in week 35, with 694 notifications.
The tropical region experienced a sustained rise in notifications from week 33 and reached a plateau between weeks 35 and 38 with a mean weekly notification count of 203 during this period.

For more information: QLD Health - Preventable Diseases                                                                                                                                                                                                                                                                                                                                                                                                             

South Australia

4 December 2016

One hundred and eight-three cases of influenza were reported this week with 152 cases being characterised as influenza A and 31 as influenza B. For the week of review cases comprised of 74 males and 109 females, with a median age of 59 years. Sixteen (9%) notifications were for children aged less than 10 years and 73 (40%) notifications for persons aged 65 years or greater. There have been 7,406 cases of influenza notified year-to-date, compared with 15,601 cases reported for the same period last year.

For more information: Communicable Diseases Control Branch

Tasmania

19 September 2016

This report describes influenza activity in Tasmania during August and the first week of September 2016. Available data over this period indicate:

The 2016 winter influenza season continued in August with a steep increase and peak in weekly notifications. During the first week of September, influenza remained at increased levels across Tasmania.

A corresponding increase in laboratory testing occurred during this time.

Influenza-related hospitalisations at the Royal Hobart Hospital increased during August.

Influenza A virus was the most common cause of laboratory confirmed Influenza. The strains circulating during August 2016 were A(H3N2) and A(H1N1)pdm09. The 2016 annual vaccine covers these strains.

Syndromic surveillance of influenza-like illness by General Practice and FluTracking also indicated increasing influenza during August.

The 2016 winter flu season commenced in late July. During August there was a significant increase in influenza notifications, with weekly counts peaking at the end of the month. Notifications declined during the first week of September but remained elevated.

There were 339 notifications of influenza during August and a further 183 during the first week of September. A total of 682 influenza notifications have been received since the start of 2016. The 499 notifications up to the end of August 2016 was less than the January-to-August period of 2015 (833 notifications) and around the average for the five years 2011-15 (536 notifications).

Influenza increased in all Tasmanian regions during August and the first week of September. Influenza A virus remained the most common cause of influenza in Tasmania during this time: isolated in 507 out of 522 notifications. Additional laboratory typing showed an almost-equal distribution of strains A(H1N1)pdm09 and A(H3N2). The 2016 annual influenza vaccine covers both of these strains. See Annual Influenza Vaccine.

Since the start of 2016 there have been four outbreaks of influenza A reported in three residential care facilities and one hospital ward.

For more information: Communicable Diseases Prevention - FluTAS

Victoria

30 October 2016

Influenza-like illness (ILI) surveillance indicates activity is at baseline levels.

The number of notified laboratory confirmed influenza cases for the year to 30 October is 38% lower than at the same time in 2015. Of the notified influenza cases, 94% have been type A. One VicSPIN swab was positive for influenza: influenza A(H3N2).

Influenza and ILI surveillance systems have returned to inter-seasonal levels, indicating that the 2016 season is over, after peaking between late August and early September.

For more information: Victorian Infectious Diseases Reference Laboratory

Western Australia

11 December 2016

This will be the final Virus WAtch for 2016.  

Summary: Indicators of ILI and influenza activity are at inter-seasonal levels.

There is a low level of residual influenza A/H3N2 and influenza B activity.

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.

10 - 23 October 2016

Influenza-like-illness levels decreased to baseline level. 

7 Cases of influenza have been detected in this reporting period:
4 x Influenza A 

3 x Influenza B 

13% Influenza positivity during the reporting period. 

439 Cases of influenza have been detected this year: 348 x Influenza A and 91 x Influenza B 

Nationally, ILI notifications decreased over the period with 62 and 85 notifications in weeks 41 and 42 respectively. ILI rates reported in this period were lower with 4 and 7 cases weighted / 3 and 6 cases unweighted per 1000 consultations in weeks 41 and 42 respectively, compared to 5 and 7 cases weighted 5 and 7 unweighted per 1000 consultations in weeks 39 and 40 respectively. For the same reporting period in 2015, ILI rates were slightly lower at 4 and 5 cases weighted / 4 and 5 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.

16 October 2016

Low levels of influenza-like illness activity.

This survey was sent on Monday, 17 October 2016 at 01:13 AM and by 09:00 AM, Thursday 20 October we had received 22767 responses (22046 last week) from 13718 people responding for themselves and 9049 household members across Australia.

Across Australia, fever and cough was reported by 1.4% of vaccinated participants and 1.4% of unvaccinated participants. Fever, cough and absence from normal duties was reported by 1.0% of vaccinated participants and 0.8% of unvaccinated participants.

For participants this week, 13740/22767 (60.4 %) have received the seasonal vaccine so far. Of the 4462 participants who identified as working face-to-face with patients, 3581 (80.3%) have received the vaccine.

For more information, or to enrol: Flu Tracking

New Zealand

27 November 2016

During November (31 October–27 November 2016), influenza activity was very low among consultation-seeking patients nationwide. Influenza activity was also low among those hospitalised ICU patients in Auckland and Counties Manukau District Health Boards. 

ILI surveillance: Twenty patients with influenza-like illness consulted sentinel general practices in 20 DHBs. The monthly ILI incidence was 4.2 per 100 000 patient population.

For more information:  NZ Flu Surveillance