Vaccination is crucial in maintaining individual and population health. Australia’s National Immunisation Program has been active since 1997 and is regularly updated as new vaccines, technology and surveillance data become available. It is therefore important that GPs have access to the most up-to-date information and resources to best advise patients, especially more vulnerable groups including children, older people, pregnant women and Aboriginal and Torres Strait Islander people.
Immunisation in Australia started in 1804 with the first smallpox vaccine, culminating in the National Immunisation Program (NIP), which began in 1997. Since then the program has expanded to include new vaccines, altered schedules and novel monitoring tools as new technology and evidence have become available. Since early 2019, there have been a number of changes to immunisation recommendations and this article aims to inform GPs on what is new, who to ask for help and where to find further information. Some practice points on vaccination are summarised in Box 1.
Influenza is a viral illness of the respiratory tract caused by influenza A and B viruses. These viruses cause major and minor epidemics of seasonal influenza in most years, usually during the winter months but can be present throughout the year (Figure 1), especially with increasing overseas travel.1 Severe complications of influenza include pneumonia, myocarditis, bacterial coinfection, encephalitis and death. Children, older people, pregnant women, Aboriginal and Torres Strait Islander (Indigenous) people and people with comorbidities have a higher risk of complication from influenza compared with the general population.2,3
Influenza vaccination for people of Aboriginal or Torres Strait Islander background
Aboriginal and Torres Strait Islander people have a high burden of disease from influenza and influenza-related complications.2,3 The risk of influenza-related hospitalisations between 2006 and 2010 was two to six times higher among people of Indigenous background compared with non-Indigenous people.2 Until 2019, the seasonal influenza vaccine was nationally funded for Indigenous children aged 6 months to 5 years and Indigenous people aged 15 years and over. To close the gap, the seasonal influenza vaccine is now funded for all Aboriginal and Torres Strait Islander people aged 6 months and over.4 In July 2019, the Pharmaceutical Benefits Advisory Committee recommended listing of the quadrivalent influenza vaccine on the NIP for all children aged 6 months to 5 years from 2020.5
Influenza vaccination for older people
People aged 65 years and over have the highest influenza-related mortality and decreased effectiveness to standard trivalent influenza vaccine (TIV) compared with the younger population.2,6 To improve the immune response to the influenza vaccine in this age group, ‘enhanced’ TIVs were developed. Two types of enhanced vaccine are available in Australia: a high-dose influenza vaccine that contains four times the haemagglutinin content of standard TIVs; and an adjuvanted influenza vaccine that contains adjuvant MF59 in addition to the standard haemagglutinin dose of each strain.4,7 These vaccines increase protection compared with standard-dose TIVs, especially against influenza A (H3) strain, which causes a more common and severe disease in older people.4,6,8-10 Clinical trials have shown reduced laboratory-confirmed influenza and influenza-related deaths in people aged 65 years and over who were vaccinated with enhanced TIVs compared with standard TIVs.8-10 Moreover, the improved efficacy of enhanced TIVs against influenza A is likely to offset the loss of protection against the additional influenza B lineage found in the quadrivalent vaccine.4
In 2018, enhanced TIVs were recommended in preference to the quadrivalent influenza vaccines for people aged 65 years and over. Active surveillance of the safety of the 2019 influenza vaccine in people aged 65 years and over commenced on 1 April 2019, with data showing reported events following immunisation were consistent with expected outcomes: most people (94%) did not have any adverse reaction; of the 6% with reactions, the most common adverse effects were injection site reactions, fevers and rash; only 0.3% required medical attendance.11,12 The adjuvanted TIV is funded through the NIP for people aged 65 years and over and the high-dose TIV is available privately.4