Influenza vaccination and older people
The importance of influenza vaccination of older people extends beyond prevention of acute infection.
Influenza vaccination provides older people with low to modest protection against influenza infection but can also reduce influenza disease severity and complications in older people who have been vaccinated but subsequently get influenza. Influenza-related death, hospitalisation, and increases in disability or frailty are lower in older people who receive influenza vaccination compared with those who do not.
Influenza vaccine efficacy for the prevention of acute myocardial infarction (AMI) following influenza is between 19% and 45%, which is similar to the effect of other measures to lower cardiovascular disease risk factors such as smoking cessation, use of statins and treatment of hypertension. Repeated annual influenza vaccination has a positive cumulative effect of greater protection against influenza complications and hospitalisation compared with only ever being vaccinated against influenza once.
Prevention of disease or reduction in disease severity and complications are critical for older people to help prevent the sequelae of increasing dependence, frailty and premature death associated with illness.
Increasing the number of older people vaccinated against the disease annually can have a significant impact on improving health outcomes in older people when influenza is circulating in our community.
Effectiveness of influenza vaccination in older people
Protection against infection
Evidence suggests the effectiveness of influenza vaccination in the older person living in the community is low to modest. Demcheli et al. (2018) recently updated their 2010 Cochrane Review and suggests vaccine effectiveness is 58% (34–73%) against laboratory confirmed influenza. Advancing age and increasing frailty6 limit an older person’s response to vaccines and decrease vaccine efficacy against acute infection.
Additional preventative strategies to reduce older people’s risk of exposure to influenza are also important. These include influenza vaccination of those who are in close contact with older people, for example living or working with older people. A reduction in circulating influenza disease/increase in herd immunity in the community through increased influenza vaccination coverage provides extra protection for the older person as it reduces the likelihood of transmission of influenza to the older person.
Protection against serious complications
Older people who have been vaccinated but subsequently get influenza are less likely to develop a severe illness, be hospitalised or require admission to an intensive care unit. Influenza vaccination has also been associated with a 36% (95% confidence interval 16–51%) lower risk of major adverse cardiovascular events, i.e. hospitalisation or death related to unstable angina, coronary artery obstruction requiring urgent revascularisation, acute myocardial infarction (AMI), heart failure, or ischaemic stroke.
Studies show influenza vaccine efficacy for the prevention of acute myocardial infarction (AMI) during the year following influenza illness is between 19% and 45%, which is similar to other measures to reduce cardiovascular disease risk factors such as smoking cessation (32–43%), statin use (19–30%) and treatment of hypertension (17–25%).
Influenza vaccination is increasingly being shown to have a role in reducing influenza-related complications including heart failure, haemorrhagic stroke, acute coronary syndrome, and respiratory failure in older people with underlying chronic conditions. Influenza vaccine effectiveness against pneumonia for the older person living in the community and the frail older person living in care range from 25% to 53%. Vaccination of frail older people is still very important as it can reduce their risk of influenza-related hospitalisation, pneumonia or death.
An increasing body of evidence supports the important role of prior and current season influenza vaccination in reducing the risk of influenza related hospitalisation with severe illness, ischaemic stroke, heart failure and acute coronary syndrome or respiratory disease. Vaccinated adults with heart failure are more likely to survive if they have received regular annual influenza vaccinations.
Safety of influenza vaccination in older people
As well as the common influenza vaccination responses, headache, muscle aches and fatigue may occur in older adults. Symptoms may appear influenza-like. However, the influenza vaccines used in New Zealand do not contain live viruses and cannot cause influenza.
Influenza vaccines can be administered to people on anticoagulants, including aspirin, dabigatran (PRADAXA®), enexoparin (CLEXANE®), heparin, rivaroxaban (XARELTO®), ticagrelor (BRILINTA™) and warfarin. After vaccination, apply firm pressure over the injection site without rubbing. After vaccination, apply firm pressure over the injection site without rubbing for 10 minutes to reduce the risk of bruising.
Please refer to the Medsafe website www.medsafe.govt.nz for the PRADAXA, CLEXANE, XARELTO and BRILINTA™ data sheets.
Zostavax® and annual influenza vaccination
- Annual influenza immunisation is recommended and funded for adults aged 65 years or over.
- One Zostavax is recommended for adults aged 65 years to under 80 years. This dose is also funded.
- Zostavax and influenza vaccine can be administered at the same visit.
- Zostavax is only given as a single dose – it IS NOT administered every year that an eligible adult receives their influenza vaccination.
Recording influenza vaccination of older people on the National Immunisation Register (NIR)
Influenza vaccination of older people should be recorded on the NIR to help monitor vaccination coverage and assess influenza protection. For more information, please refer to the section Recording influenza vaccinations on the National Immunisation Register on page 11 of the Flu Handbook 2021.