Status:
Resolved
Health advisory:
170006
Date Issued:
10 Jul 2017
Issued by:
Dr Brett Sutton, Deputy Chief Health Officer (Communicable Disease), Victoria
Issued to:
Health professionals and consumers

Key messages

  • Seasonal influenza rates are up, with the overall number of confirmed influenza cases in Victoria up 81 per cent, compared to the same time in 2016.
  • It's not too late to vaccinate to provide protection against the top four circulating strains of influenza.
  • Most reported cases are type A (78 per cent) but the national trend is towards more type B.
  • Influenza is a Group B disease that must be notified in writing within 5 days of laboratory confirmation.

What is the issue?

Influenza is an acute respiratory disease. 2,851 cases of influenza have been reported to the department in the year to date. There is plenty of vaccine available and it's never too late to vaccinate.

Who is at risk?

Severe disease from seasonal influenza is more likely with advanced age; infancy; chronic conditions, such as heart or lung disease, renal failure, diabetes and chronic neurological conditions; immuno-compromise; obesity, pregnancy and smoking. Aboriginal and Torres Strait Islander people also generally experience more severe illness.

Severe disease may also occur in otherwise healthy children and young adults. Annual attack rates in the general community are typically five to ten per cent, but may be up to 20 per cent in some years.

Symptoms and transmission

Symptoms include fever, headache, myalgia, lethargy, coryza, sore throat and cough. Infections in children may also be associated with gastrointestinal symptoms such as nausea, vomiting and diarrhoea. Croup is a common presentation in children.

Most symptoms resolve within seven days, although the cough may persist for longer. Complications of influenza include middle ear infections, secondary bacterial pneumonia and exacerbation of underlying chronic health conditions.

A clinical diagnosis can be confirmed by culture or antigen testing of appropriate respiratory specimens, such as nasopharyngeal aspirate or nose and throat swabs, taken within five (preferably two) days of onset. It can also be confirmed by serology performed on blood specimens taken during the acute and convalescent stages, but this is less useful for clinical or outbreak management.

The diagnosis can be confirmed in the laboratory by one or more of the following:

  • detection of influenza virus by culture or nucleic acid testing, most commonly polymerase chain reaction (PCR) testing
  • a single high influenza-specific antibody titre or fourfold increase between acute and convalescent samples.

Prevention / treatment

Free annual influenza vaccine is provided and recommended for the following groups in Victoria:

  • people aged 65 years and older
  • pregnant women at any stage of pregnancy
  • Aboriginal and Torres Strait Islander people aged 6 months to 4 years of age inclusive, and 15 years and older
  • residents of nursing homes and other long-term care facilities
  • those aged 6 months or older with conditions predisposing to severe illness following influenza infection.

Both the funded National Immunisation Program influenza vaccine and non-funded vaccine can be obtained from GPs or accredited immunisation providers. This includes pharmacists participating in Victoria's Pharmacist-administered vaccination program.

Clinical information

Vaccine orders: Immunisation providers can order the National Immunisation Program influenza vaccine by visiting health.vic's Vaccine order forms page. Completed order forms should be emailed to orders@onelink.com.au or faxed to 1300 682 507. Please allow three business days for processing and delivery of your vaccine order.

health.vic: Information about influenza

Notifications: via http://ideas.health.vic.gov.au or by telephone on 1300 651 160 or faxed on 1300 651 170.

Consumer information

Better Health Channel: fact sheet on influenza immunisation