fluTAS 2018 Report 2

fluTAS 2018 Report 2

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Public Health Services produce the fluTAS Report to provide information about the level of influenza (flu) in Tasmania. Multiple surveillance data sources are used to obtain measures of influenza activity in the community.

This surveillance report describes influenza activity in Tasmania during the period 1 January to 31 May 2018.

May 2018 Update

  • The 2018 influenza season has not begun.
  • There was low inter-seasonal influenza activity during May.
  • Other respiratory pathogens including Rhinovirus and Respiratory Syncytial Virus appear to be the major contributors of influenza-like illness in the community.
  • No outbreaks of influenza have been reported in Tasmania.

Influenza Notifications

There were 13 notifications of laboratory-confirmed influenza during May 2018 (Table 1). This was lower than the five-year May average (22 notifications) and consistent with the typically low inter-seasonal influenza activity (Figure 1).

No outbreaks of influenza were notified during January to May 2018.

This line graph displays each flu season as weekly notification counts for the 52 weeks of each year. The years 2014 to 2018 are overlaid on top of each other. 2017 was the year with the highest seasonal peak of over 450 notifications per week during mid-September. 2014 to 2016 each had a peak during August to September. The 2018 line stops at week 22; the last week of May. Similar to previous years the height of this line is almost touching the zero mark, indicating typical low inter-seasonal activity in Tasmania.

Figure 1: Notifications of influenza in Tasmania, by week, 1 January 2014 to Sunday 3 June 2018

From 1 January to 31 May 2018 there were 102 notifications of laboratory-confirmed influenza. Subtyping was reported for 14 Influenza A results (Table 1). The majority of notifications (61) were in the southern region of Tasmania. There were 22 notifications for residents of the North and 18 for the North-West. One overseas visitor was diagnosed with influenza in Tasmania during this period.

Table 1: Notifications of influenza in Tasmania by subtype and month, 1 January to 31 May 2018

 

Jan

Feb

Mar

Apr

May

2018 YTD

Influenza A

9

15

17

10

7

58

A(H1N1)

0

2

0

0

0

2

A(H3N2)

2

5

2

3

0

12

A (not typed)

7

8

15

7

7

44

Influenza B

8

11

8

11

6

44

Total Influenza

17

26

25

21

13

102

Notifications of influenza are based on positive laboratory tests. Many people with flu-like illness choose not to attend medical care, or are not tested when they attend for a variety of reasons. As a result the notifications only represent a small proportion of influenza illness in the community.

Laboratory testing

Influenza testing

A wide range of pathogens (mostly viruses) commonly cause winter coughs, colds and influenza-like illnesses. The best test for influenza is a PCR test, which detects influenza virus genetic material (RNA). The number of influenza PCR tests being performed by Tasmanian laboratories can indicate the level of respiratory illness in the community.

Of the 102 notifications of influenza between January and May 2018, 31 (30 per cent) were tested using a serology test and 71 (70 per cent) were tested using a PCR test.

This vertical bar graph displays weekly tests for the whole of 2018. Data presented ends at the end of May 2018, on week number 22. Weekly testing activity averaged approximately 80 tests per week until late-April; increasing to more than 160 tests per week at the end of May. A black line appears in front of the bars indicating the changing percentage of tests each week that are positive for influenza. This line indicates low activity averaging four per cent positive until the end of April. During May almost no influenza detections are indicated: positivity ranged from zero to one per cent per week.

Figure 2: Statewide Influenza PCR testing, 1 January to Sunday 3 June 2018

During May, 771 PCR tests for influenza were conducted. This represented a 42 per cent increase on the testing conducted during May 2017 (545 tests). The weekly proportion of tests positive for influenza ranged from zero to one per cent per week (Figure 2). This was consistent with expected low inter-seasonal influenza activity.

Other respiratory pathogens

The monitoring of non-influenza respiratory pathogen activity provides an indication of the proportion of respiratory infections caused by influenza. This proportion can give us some information about the timing of the season, as generally a larger proportion of respiratory illness is caused by influenza during the influenza season.

The Royal Hobart Hospital (RHH) performs a PCR test on samples from patients presenting with a respiratory illness that detects influenza and multiple other pathogens that cause similar symptoms. These data are only available from the RHH, which is a public laboratory and the majority of specimens collected and tested are from emergency department presentations and hospitalised patients. FluTAS reports on Influenza A, Influenza B, and seven other respiratory viruses most commonly reported in Tasmania.

There were 375 tests performed during May 2018, which represented a 43 per cent increase on testing during May 2017 (262 tests).

The most commonly detected pathogens were Rhinovirus (52 per cent), Respiratory Syncytial Virus (RSV) (25 per cent) and Parainfluenza (10 per cent) (Figure 3). Influenza A virus was not reported to be detected in any tests during May 2018. Influenza B virus was detected in only two tests out of the 375 performed.

The proportion of May 2018 tests with no pathogens detected (44 per cent) was lower than May 2017 (50 per cent).

This vertical bar graph displays pathogens detected each week for the whole of 2018. Data presented ends at the end of May 2018, on week number 22. There are nine pathogens listed in the graph legend: Adenovirus, Metapneumovirus, Mycoplasma Pneumoniae, Parainfluenza, Pertussis, RSV, Rhinovirus, Influenza A and Influenza B. Rhinovirus has been the most frequently detected pathogen since the start of 2018. Weekly pathogen detections averaged 21 per week until early May; then increasing to above 50 detections per week. A component of the May activity is an increase in detections of RSV. A very small number of weekly Influenza A and Influenza B results have occurred on and off during the year to date.

Figure 3: Respiratory pathogen detections, 1 January to Sunday 3 June 2018.

National surveillance systems

FluCAN

The Influenza Complications Alert Network (FluCAN) reports on influenza-related hospitalisations and complications in sentinel hospitals Australia-wide during each influenza season. This system aims to provide an indication of severity of the influenza season and identify groups at higher risk of influenza related hospital admission. The details of recent FluCAN activity are published in the Australian Influenza Surveillance Report (see Interstate Activity).

From 3 April to 1 June 2018 there were 48 hospital admissions of confirmed influenza reported by sentinel hospitals Australia-wide. Six were direct admissions to an ICU. During this period FluCAN described activity across participating hospitals as ‘low early-season activity’.

To date there have been no influenza admissions reported to FluCAN by the one participating Tasmanian hospital (Royal Hobart Hospital).

FluTracking (Community Syndromic Surveillance)

FluTracking is a weekly online survey that asks participants to report whether they have had fever and/or cough in the preceding week. It is a joint initiative of Newcastle University, Hunter New England Population Health and the Hunter Medical Research Institute. FluTracking information is available at www.flutracking.net and on Facebook www.facebook.com/Flutracking

FluTracking recommenced on 30 April 2018. An average of 3 150 Tasmanians have participated each week; an increase on 2017 participation (average 2 710 Tasmanians per week).

Between 30 April and 3 June 2018 an average of 1.3 per cent of Tasmanian participants reported a new episode of ILI (fever plus cough) each week (Figure 4). Of these participants, two-thirds (67%) also reported absenteeism from normal duties due to illness.

This line graph displays the proportion of Tasmanian FluTracking participants reporting a new episode of fever and cough each week during 2017 and this year, 2018. The red 2017 line covers the period from late April to early October 2017. New episodes of fever and cough in Tasmanian participants peaked at around three point five per cent during August and September 2017. A short black line from late-April to the end of May indicates 2018 activity. The 2018 line sits at or below the one point five per cent mark: a similar low proportion of fever and cough in participants when compared to April and May 2017

Figure 4: Percentage of Tasmanian FluTracking participants reporting fever and cough, week ending Sunday 3 June 2018

ASPREN (General Practice Syndromic Surveillance)

The Australian Sentinel Practices Research Network (ASPREN) includes registered sentinel GPs across Australia who report fortnightly on the number of patients presenting with ILI. Five GPs are registered in Tasmania.  ASPREN is a joint initiative of the Royal Australian College of General Practitioners and University of Adelaide. Further information is available at www.dmac.adelaide.edu.au/aspren

ASPREN reporting for the period 1 January to 22 April 2018 indicated activity ranging from none to baseline# in participating Tasmanian practices. Nationally, presentations of ILI to participating GPs remain steady at baseline levels across most of Australia.

# Baseline activity means only one to three consultations out of every 1 000 were due to an ILI presentation.

Interstate activity

The Australian Influenza Surveillance Report is compiled from a number of data sources including laboratory-confirmed notifications to National Notifiable Diseases Surveillance System, sentinel influenza-like illness reporting from general practitioners and emergency departments, workplace absenteeism and laboratory testing. The routine Australian Influenza Surveillance Report is published by the Australian Government Department of Health.

National reporting for 2018 has not commenced. Past reports including a summary of the 2017 influenza season are available at www.health.gov.au/flureport

Annual Influenza Vaccine

Composition of 2018 influenza vaccines

The annual influenza vaccine is reviewed late each year, aiming to produce vaccines for the following year that provide protection from influenza strains likely to be common during winter. Advice on the formulation of annual influenza vaccines is provided to the Therapeutic Goods Administration by the Australian Influenza Vaccine Committee (AIVC): www.tga.gov.au/committee/australian-influenza-vaccine-committee-aivc

The AIVC met in October 2017 to recommend the influenza viruses to be used in influenza vaccines for 2018. The TGA accepted the recommendations of the AIVC.

Composition of influenza vaccines in 2018:

  • Trivalent (three-strain) vaccines should contain the following
    • A (H1N1): an A/Michigan/45/2015 (H1N1)pdm09-like virus
    • A (H3N2): an A/Singapore/INFIMH-16-0019/2016 (H3N2)-like virus
    • B: a B/Phuket/3073/2013-like virus
  • Quadrivalent (four-strain) vaccines should contain the trivalent strains listed above plus an additional B strain
    • B: a B/Brisbane/60/2008-like virus.

Further information on the composition of influenza vaccines is available at www.tga.gov.au/aivc-recommendations-composition-influenza-vaccine-australia

Is vaccination recommended?

Annual influenza vaccination is recommended for anyone over the age of six months who wishes to reduce the likelihood of influenza and its complications. Annual vaccination can help to reduce the spread of influenza and protect vulnerable members of the community.

Influenza vaccines in 2018 are free# in Tasmania for people at greater risk of contracting and developing severe complications from influenza. Free vaccine is available through General Practitioners for the following people:

  • All children aged from six months to under five years (state funded in 2018)
  • Aboriginal and Torres Strait Islander people aged 15 years and over
  • Adults aged 65 and over (two enhanced trivalent vaccines in 2018)
  • Pregnant women at any stage in their pregnancy.
  • Adults and children aged from six months with chronic medical conditions such as heart, lung, liver or kidney diseases, asthma, diabetes, cancer, impaired immunity and neuromuscular conditions.

For more information see flu.tas.gov.au or beta.health.gov.au/topics/immunisation

# Please note there may be a consultation fee for the healthcare provider to administer the vaccine.

Further Information

For the latest information on influenza in Tasmania visit flu.tas.gov.au

Past fluTAS reports are available at dhhs.tas.gov.au/publichealth/communicable_diseases_prevention_unit