Author Dr Penny Abbott
Expert reviewer Professor Anne Chang
Influenza is a common respiratory disease caused by influenza A and B viruses. These viruses cause minor or major epidemics of seasonal influenza in most years, usually during the winter months. In 2009, the world experienced its first pandemic influenza since 1968 after the emergence of the novel H1N1 influenza strain. Aboriginal and Torres Strait Islander people were disproportionately affected by the H1N1 influenza epidemic, being four times more likely to be admitted to hospital and accounting for 13% of the total deaths.3,26,27 There are calls for Aboriginal and Torres Strait Islander people to be acknowledged as a high risk group requiring specialised planning to manage future influenza outbreaks.28
The consequences of influenza in children and healthy adults at low risk are mainly absenteeism from school and work. However, severe disease is more likely with advanced age, lack of previous exposure to antigenically related influenza virus, chronic conditions such as heart or lung disease, renal failure and diabetes, chronic neurological conditions, pregnancy and smoking.2,29
Administration of the current influenza vaccine before winter, provides protection against the disease and its complications in up to 70% of those who are vaccinated.27 Immunisation should be given annually, preferably in March to April before the Australian flu season.2
In healthy adults, influenza vaccines have only a modest effect in reducing influenza symptoms and working days lost and no effect on hospital admission or complication rates.30
Recommendations for vaccination of all individuals over 65 years of age and all individuals over the age of 6 months with chronic disease is made on the basis of the higher risk of hospitalisation and complications from influenza in these groups.2,31–33 As yet there is limited and conflicting evidence on the effectiveness of influenza vaccination for people aged 65 years and over and for many groups of people with chronic disease,30,34–36 though the evidence is clearer that influenza vaccination is effective in decreasing complications in COPD23,37 and diabetes.38,39
Influenza vaccination has been found to be effective in reducing infection in children.29,40–42 During the 2010 influenza season, an excess number of cases of febrile reactions and febrile convulsions were observed in paediatric populations following immunisation with one of the registered seasonal trivalent influenza vaccines. This led to the suspension of the provision of this particular vaccine to children under the age of 5 years, however the Therapeutic Goods Administration and the Australian Technical Advisory Group on Immunisation continued to recommend other brands of seasonal influenza vaccine for children for whom it was indicated.31 There is as yet limited evidence that influenza immunisation for healthy children leads to a reduction in community transmission of influenza.29,43 Influenza vaccination during pregnancy is recommended based on the increased morbidity and mortality of pregnant women who contract influenza, coupled with no evidence of harm from immunisation in pregnancy.2,44
Australian guidelines recommend annual influenza vaccine should be given to all Aboriginal and Torres Strait Islander people aged 15 years and over in view of their substantially increased risk of hospitalisation and death from influenza and pneumonia.2 Effective strategies to promote influenza immunisation should be undertaken at a community level, particularly the use of recall and reminder systems,20,25,33,45 and should be tailored to the needs of the community concerned.
Infection control measures such as handwashing, particularly with young children, can be effective in preventing transmission of influenza.46 Healthcare providers can potentially transmit influenza to high risk patients and it has been shown that vaccinating the former protects those at high risk.2,47 Implementing barriers to transmission, such as isolation, and hygienic measures (wearing masks, gloves and gowns) can be effective in containing respiratory virus outbreaks or in hospital wards.46 The more expensive (but uncomfortable) N95 respirators might be superior to simple masks. It is unclear if adding virucidals or antiseptics to normal handwashing with soap is more effective.46
Two classes of antiviral drugs are available for the treatment and prevention of influenza: the neuraminidase inhibitors, zanamivir and oseltamivir, which are active against both influenza A and B; and the adamantanes, amantadine and rimantadine, which are only active against influenza A.27 The neuraminidase inhibitors (NIs) oseltamivir (taken orally) and zanamivir (inhaled) are approved for use in Australia for the treatment and prevention of influenza A and B.48,49 Systematic reviews on the effectiveness of NIs for influenza prophylaxis in inter-pandemic years have come to conflicting conclusions. They generally show limited effectiveness in preventing influenza infection, its transmission and its complications in otherwise healthy adults.50,51 Consequently NIs are not recommended for the prevention of influenza in healthy adults.27,48,50,51 They may, however, have a role in the prophylaxis of at risk contacts of people with influenza, particularly during pandemics.27,50 Studies of post-exposure prophylaxis for 10 days have enrolled patients within 36–48 hours of exposure to a household contact, and have demonstrated a protective efficacy of 78–89% compared with expectant treatment at the onset of symptoms.48
The decision to use NIs for prevention of influenza in at risk individuals depends on the assessment of the likelihood of influenza, the likely benefits of treatment based on the presence of comorbidities and the risk of developing complications. Treatment must be initiated early in order to maximise efficacy.48,50 When initiated promptly, antiviral therapy can shorten the duration of influenza symptoms by 1–3 days; the benefit is greatest when given within the first 24–30 hours and in patients with fever at presentation. Little to no benefit has been demonstrated when treatment is initiated 2 days or more after the onset of uncomplicated influenza.
The availability of antiviral drugs, including public health policies regarding the distribution of the national stockpile, is also taken into consideration in a pandemic situation.48 Post-exposure prophylaxis with NIs continues to be recommended for vulnerable Aboriginal and Torres Strait Islander household contacts during influenza outbreaks within communities.52
Recommendations: Influenza prevention
|Preventive intervention type||Who is at risk?||What should be done?||How often?||Level/strength of evidence|
||All people aged ≥15 years
||Offer influenza vaccine in the pre-flu season months for the prevention of influenza (March to April)
|Children with chronic illness aged 6 months to 14 years
|Women who are pregnant or planning a pregnancy
||Part of routine antenatal care (see Chapter 9: Antenatal care)
|Children under 6 months of age
||Influenza vaccination is not recommended
||Household contacts of a person with influenza
||Good hygiene practice, such as frequent handwashing and covering the mouth on coughing or sneezing, is recommended to decrease the spread of influenza, particularly to reduce transmission from children to other household members
||Minimise exposure risk to patients with influenza-like illness by adhering to current infection control guidelines
In addition to standard infection control procedures, personal protective equipment is recommended during influenza pandemics48,53
||Neuraminidase inhibitors (NIs) are generally not indicated for the prevention of influenza
|People at high risk of influenza complications, where there are high levels of circulating virus
||Consider NIs for high risk individuals in close contact with someone with a proven case of influenza (ideally initiated within 48 hours), particularly in a pandemic situation or where there is high levels of circulating virus
||Primary care, community based strategies to improve vaccination levels, particularly using reminder/recall systems, should be implemented
||Activities should also focus on increasing community awareness of benefits and timeliness of vaccines for vaccinations and enhancing access to vaccination services
- National Health and Medical Research Council. The Australian immunisation handbook, 9th edn. Canberra: Commonwealth of Australia, 2008. Cited October 2011. Available at www.health.gov.au/ internet/immunise/publishing.nsf/ content/handbook-home.
- Australian Institute of Health and Welfare. Asthma, chronic obstructive pulmonary disease and other respiratory diseases in Australia. Canberra: AIHW, 2010.
- McKenzie DK, Abramson M, Crockett AJ, et al. The COPD-X Plan: Australian and New Zealand guidelines for the management of chronic obstructive pulmonary disease 2011. COPDX, 2011. Cited October 2011. Available at www.copdx.org.au.
- Jacobson V, Szilagyi P. Patient reminder and patient recall systems to improve immunization rates. Cochrane Database Syst Rev 2005;Jul 20;(3):CD003941.
- Global Initiative for Chronic Obstructive Lung Disease. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease. Bethesda: Global Initiative for Chronic Obstructive Lung Disease, 2009. Cited October 2011. Available at www.guideline.gov/content.aspx?id=25648.
- Guide to Community Preventive Services. Universally recommended vaccinations: community-based interventions implemented in combination (abbreviated). The Community Guide, 2010. Cited October 2011. Available at www.thecommunityguide.org/ vaccines/universally/communityinterventions .html.
- Rudge S, Massey PD. Responding to pandemic (H1N1) 2009 influenza in Aboriginal communities in NSW through collaboration between NSW Health and the Aboriginal community-controlled health sector. NSW Public Health Bull 2010;21(1-2):26–9.
- Respiratory Expert Group. Therapeutic guidelines: respiratory. Version 4. Melbourne: Therapeutic Guidelines Limited, 2009.
- Miller A, Durrheim AD. Aboriginal and Torres Strait Islander communities forgotten in new Australian National Action Plan for Human Influenza Pandemic: ‘Ask us, listen to us, share with us’. Med J Aust 2010;193(6):316–7.
- Jefferson T, Rivetti A, Harnden A, Di Pietrantonj C, Demicheli V. Vaccines for preventing influenza in healthy children. Cochrane Database Syst Rev 2008;Apr 16;(2):CD004879.
- Jefferson T, Di Pietrantonj C, Al-Ansary LA, Ferroni E, Thorning S, Thomas RE. Vaccines for preventing influenza in the elderly. Cochrane Database Syst Rev 2010;Feb 17;(2):CD004876.
- Australian Technical Advisory Group on Immunisation. Updated advice on the use of pandemic and seasonal influenza vaccines in children <10 years of age. Canberra: DoHA, 2010. Cited October 2011. Available at www.immunise.health.gov.au/ internet/immunise/Publishing.nsf/content/ A1ECFAA9C9857C11CA25776D000471C2/$File/ATAGI- advice-fluvac-under10yo-26aug10.pdf.
- Council of the European Union. Council recommendation of 22 December 2009 on seasonal influenza vaccination. Official Journal of the European Union (serial on the internet), 2009. Cited October 2011. Available at http://eur-lex.europa.eu/ LexUriServ/LexUriServ.do?uri=OJ:L: 2009:348:0071:0072:EN:PDF.
- Fiore AE, Uyeki TM, Broder K, et al. Prevention and control of influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP), 2010. MMWR Morb Mortal Wkly Rep 2010;59(8):1–62.
- Dharmaraj P, Smyth RL. Vaccines for preventing influenza in people with cystic fibrosis. Cochrane Database Syst Rev 2009 Oct 7;(4):CD001753.
- Goossen GM, Kremer LC, van de Wetering MD. Influenza vaccination in children being treated with chemotherapy for cancer. Cochrane Database Syst Rev 2009;Apr 15;(2):CD006484.
- Cates CJ, Jefferson TO, Rowe BH. Vaccines for preventing influenza in people with asthma. Cochrane Database Syst Rev 2008;Apr 16;(2):CD000364.
- Poole P, Chacko EE, Wood-Baker R, Cates CJ. Influenza vaccine for patients with chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2006;Jan 25;(1):CD002733.
- Colquhoun AJ, Nicholson KG, Botha JL, NT R. Effectiveness of influenza vaccine in reducing hospital admissions in people with diabetes. Epidemiol Infect 1997;119:335–41.
- Looijmans-Van den Akker I, Verheij TJM, Buskens E, Nichol KL, Rutten GEHM, Hak E. Clinical effectiveness of first and repeat influenza vaccination in adult and elderly diabetic patients. Diabetes Care 2006 Aug;29(8):1771–6.
- Joshi AY, Iyer VN, St Sauver JL, Jacobson RM, Boyce TG. Effectiveness of inactivated influenza vaccine in children less than 5 years of age over multiple influenza seasons: a case-control study. Vaccine 2011;27(33):4457–61.
- Heinonen S, Silvennoinen H, Lehtinen P, Vainionpaa R, Ziegler T, Heikkinen T. Effectiveness of inactivated influenza vaccine in children aged 9 months to 3 years: an observational cohort study. Lancet Infect Dis 2011;11(1):23–9.
- Katayose M, Hosoya M, Haneda T, et al. The effectiveness of trivalent inactivated influenza vaccine in children over six consecutive influenza seasons. Vaccine 2011;29(9):1844–9.
- Cohen SA, Chui KK, Naumova EN. Influenza vaccination in young children reduces influenza-associated hospitalizations in older adults, 2002–2006. J Am Geriatr Soc 2011;59(2):327–32.
- Mak TK, Mangtani P, Leese J, Watson JM, Pfeifer D. Influenza vaccination in pregnancy: current evidence and selected national policies. Lancet Infect Dis 2008 Jan;8(1):44–52.
- Thomas RE, Russell M, Lorenzetti D. Interventions to increase influenza vaccination rates of those 60 years and older in the community. Cochrane Database Syst Rev 2010;Sep 8;(9):CD005188.
- Jefferson T, Del Mar C, Dooley L, Ferroni E, Al-Ansary LA, Bawazeer GA, et al. Physical interventions to interrupt or reduce the spread of respiratory viruses. Cochrane Database Syst Rev 2011;Jul 6;(7):CD006207.
- Pearson ML, Bridges CB, Harper SA. Influenza vaccination of health-care personnel: recommendations of the Healthcare Infection Control Practices Advisory Committee (HICPAC) and the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep 2006;55(2):1–16.
- Cheng AC, Dwyer DE, Kotsimbos AT, et al. ASID/TSANZ guidelines: treatment and prevention of H1N1 influenza 09 (human swine influenza) with antiviral agents. Med J Aust 2009;191:1–8.
- Therapeutic Goods Administration. EBS Australian Register of Therapeutic Goods: Medicines. Canberra: Australian Government, Therapeutic Goods Administration, 2011. Cited October 2011. Available at www.ebs.tga.gov.au/ ebs/ANZTPAR/PublicWeb.nsf/cuMedicines? OpenView.
- National Institute for Health and Clinical Excellence. Influenza (prophylaxis): amantadine, oseltamivir and zanamivir. TA158. London: National Institute for Health and Clinical Excellence, 2008. Cited October 2011. Available at http://guidance.nice.org.uk/TA158..
- Jefferson T, Jones M, Doshi P, Del Mar C, Dooley L, Foxlee R. Neuraminidase inhibitors for preventing and treating influenza in healthy adults. Cochrane Database Syst Rev 2010;Feb 17;(2):CD001265.
- Communicable Diseases Network Australia and Department of Health and Ageing. Guidelines for the public health management of trachoma in Australia. Canberra: Commonwealth of Australia, 2011. Cited January 2012. Available at www.health.gov.au/ internet/main/publishing.nsf/Content/cda-cdna-pubs-trachoma.htm.
- Department of Health and Ageing. Interim infection control guidelines for pandemic influenza in healthcare and community settings. Canberra: Commonwealth of Australia, 2009. Cited October 2011. Available at www.flupandemic.gov.au/ internet/panflu/publishing.nsf/Content/interim-infection-control-guidelines-1.
- Global Initiative for Asthma. Global strategy for asthma management and prevention. GIA, 2009.
- National Asthma Education and Prevention Program: Third Expert Panel on the Diagnosis and Management of Asthma. Expert panel report 3 (EPR3): guidelines for the diagnosis and management of asthma. Bethesda, MD: National Heart, Lung, and Blood Institute, 2007. Cited October 2011. Available at www.nhlbi.nih.gov/ guidelines/asthma/asthgdln.htm.