Vaccine coverage in older people
In Australia, accurate data on vaccine coverage levels are available for the paediatric vaccination program but not for vaccination coverage of older people. The most recent national survey of vaccine coverage in older adults was conducted in 2009. Estimates derived from more recent ad-hoc surveys suggest that:
- about 75 to 80% of older people receive influenza vaccines each year
- about 50% have received a pneumococcal vaccine
- about 25 to 30% have received a herpes zoster vaccine (albeit more in the 70 to 79 years age group)
- fewer than 10% have received a pertussis booster in the past 10 years.
The recent expansion of the Australian Childhood Immunisation Register (ACIR) into a whole-of-life Australian Immunisation Register (AIR) has the potential to improve data on older people over time. However, this will depend on the support of GPs to input data as they vaccinate older people. It will also require data entry at other sites where vaccines are provided, such as pharmacies. Further, the absence of a mechanism to input historical data will reduce the accuracy of coverage data for all vaccines other than the annual influenza vaccine for many years.
Burden of vaccine-preventable disease in older people
Similarly, accurate data on vaccine-preventable disease rates in older people are not available. Many older people with influenza are not tested or notified to public health authorities; presenting symptoms may be a worsening of a chronic condition, or confusion alone, and more than half of patients have no fever.5 Many patients with shingles are diagnosed clinically and are not investigated. Most patients with pertussis present with a chronic cough and do not have a swab taken. About 20% of patients presenting with a chronic cough of more than two weeks’ duration have pertussis.6 Community-acquired pneumonia is rarely confirmed as being due to Streptococcus pneumoniae (pneumococcus).
The failure to describe adequately the morbidity and mortality associated with vaccine-preventable diseases in older people is a major impediment to improving vaccine uptake. Lack of awareness of the significance of a problem reduces the likelihood of preventive action. Despite the high percentage of older people developing shingles (with 50% of 85-year-olds having had the disease7) and the seriousness of postherpetic neuralgia, a community survey conducted by a vaccine manufacturer found that only 4% of older people were concerned about the disease. The lack of understanding of the significance of these illnesses extends to healthcare providers, with few understanding the seriousness of pertussis infection for older people themselves, not only for their newborn grandchildren.
Improving vaccine uptake in older people
Some pre-conditions and requirements for improving vaccine uptake in older people are outlined in the Table.
Better understanding of disease burden and vaccine benefits
Developing a better understanding of the balance of risks versus benefits of vaccines in older people involves engaging not just health practitioners but also the public, media and governments. The initial step involves providing strong evidence about the burden of vaccine-preventable disease, put simply, and incorporating health literacy development.8 Having available product champions from among target groups as well as skilled media performers is important once messages are ready, as is engaging nontraditional partners in message development, such as groups representing aged people or people living with chronic diseases.
Although providing education to GPs that emphasises whole-of-life vaccination and vaccination of older people is necessary, opportunities also exist to involve nurse immunisers, immunisation alliances, pharmacists and key nongovernment organisations such as COTA (formerly Council on the Ageing), Diabetes Australia and other organisations representing target groups. Despite the lack of support for these ‘nontraditional’ sources of vaccination in some sectors, their scope is increasing, and they should be involved in messaging to ensure consistent activity.9 Although many older people still use traditional media, an increasing proportion access the internet, and enhanced promotional activity on social media might also improve uptake.
Largely due to immunosenescence, many vaccines are only partly effective in older people, leading to a reduced commitment to their use by both the public and health professionals. Modified messages about vaccination are required to address this. For example, although some older people develop influenza despite being vaccinated, their illness will be attenuated, and they will be less likely to be hospitalised.10 Also, new enhanced influenza vaccines produce a better response than traditional inactivated influenza vaccines. GPs need to convey the dangers of not being vaccinated.