Australia’s never-ending flu season

Flu experts are warning that high summer flu rates in 2018-19 defy usual trends making diagnostic testing and vaccination even more important.

 

Flu season usually peaks between May and October with a surge in cases after a marked drop-off in summer.

 

According to national Department of Health figures and influenza test data from Sullivan Nicolaides Pathology, 2019 is different with a higher than usual number of summer cases.

 

“It is really unusual that we have had continued flu and have not returned to our usual baseline,” says Dr Jenny Robson, a clinical microbiologist and infectious disease physician at Sullivan Nicolaides Pathology in Queensland.

 

About 40% of tests performed by her laboratory prove positive for flu at peak season, but most laboratories typically perform a suite of tests looking for several other important viruses, such as respiratory syncytial virus (RSV), parainfluenza virus and human metapneumovirus (HMPV).

 

According to the data from Sullivan Nicolaides Pathology1, the highest rate of flu diagnoses this year has been in women in their 30s.

 

Confirmed diagnoses for other respiratory viruses such as parainfluenza and rhinoviruses (that cause the common cold) were most common in young children.

 

Cases of HMPV which can progress to bronchitis or pneumonia, were also more common in young children but there were also high rates in women aged 40 and over.

 

Dr Robson says it is not yet possible to predict how bad the 2019 flu strains will be, but there have already been 55,240 laboratory confirmed cases2 and 119 flu-related deaths this year.

 

Figures from 2017 show 32% of flu hospitalisations3 were in children under 15, but the latest survey data from the Immunisation Coalition shows that only 10% of Australian parents believe that children are one of the groups recommended for flu vaccination.

 

A/Prof Ian Mackay, a virologist from The University of Queensland, says vaccination and testing are important to minimise the community impact of flu, “People tend to underestimate the seriousness of the flu because it happens every year. Young children typically have the highest number of flu cases each year and also get the sickest with higher rates of hospitalisation. Children are more likely to spread flu because of increased social contact and poor hygiene compared to adults.”

 

Dr Robson and A/Prof Mackay agree that the advantage of having a flu test is GPs can prescribe antiviral medication quickly, particularly to those at high risk of complications such as the elderly, the very young and those who have chronic medical conditions.

 

Testing also rules out the need for antibiotics as there is no reason to give antibiotics for a flu virus unless the patient has a complication that involves a bacterial infection.

 

Dr Robson says having a test has several other advantages for patients with flu-like symptoms:

  • You get a diagnosis quickly, often within 24 hours.
  • If patients know they have flu, they are more likely to stay at home and take care not to infect other people.
  • GPs can find out if the patient is in contact with high-risk people and offer preventative antivirals.
  • The information collected by pathologists helps determine how the circulating virus has changed compared with previous years, which is essential for the development of an effective vaccine for the next year.
  • Resistance to antiviral treatments can be monitored.

 

Influenza immunisation is recommended every year for:

  • Aboriginal and Torres Strait Islander people aged 6 months and over, for free under the National Immunisation Program (NIP)
  • people aged 6 months or over who have medical conditions that mean they have a higher risk of getting serious disease, for free under the NIP
  • pregnant women at any stage of pregnancy, for free under the NIP
  • people aged 65 years or over, for free under the NIP
  • all children over 6 months and all adults
  • women who are planning a pregnancy
  • people who live or work in aged care homes or long-term facilities
  • homeless people, and the people who care for them
  • healthcare workers
  • people who live or work in the same household as someone who is at high risk of serious disease from influenza
  • people who work in early childhood education and care
  • people who work in the chicken or pig industries, if there is an outbreak of bird flu or swine flu
  • people who are travelling overseas.

 

References:

  1. Sullivan Nicolaides Pathology data: https://www.snp.com.au/media/7497/20190518-snpir-influenza-graph.pdf
  2. https://www.health.gov.au/internet/main/publishing.nsf/Content/cda-surveil-ozflu-flucurr.htm/$File/flu-02-2019.pdf
  3. https://www.immunisationcoalition.org.au/news-media/influenza-vaccination-for-kids-could-be-a-game-changer/

 

5 June 2019.