Adult Immunisation – Its necessity in the healthcare sector and beyond

Eavan Daly
Eavan Daly

This past April saw the marking of World Immunisation Week, an annual health campaign developed by the World Health Organisation and serving as a timely reminder of the crucial role that vaccines and immunisation, for both the young and old, play in protecting our health and well-being, writes Eavan Daly, Country Medical Director, GSK Ireland

Aside from clean drinking water, no other intervention for public health has been as effective as vaccination1, which prevents 3.5-5 million deaths on average annually2. Yet there is always more that can be done and areas that deserve more focus, one of note being the realm of Adult Immunisation.

Globally, we are witnessing a major demographic shift as our population ages. As of 2020, people over 65 comprised 20.6% of the EU population, a 3.0 percentage point growth from the previous study a decade earlier3. By 2050, the percentage of over 65s is expected to grow to 30%4.

While the life expectancy for older adults is rising in the EU (Ireland’s average life expectancy is 83 years), unfortunately this does not necessarily mean that these extra years are lived healthier.

The natural decline of an individual’s immune system as they age, known as immuno-senescence, coupled with the underlying ailments often associated with old age (cardiovascular disease, diabetes, and COPD for example) lead to infectious diseases having a much higher morbidity, mortality for people aged 65 and over versus younger adults5. In Ireland, only 8% of those aged 58 or older report having no chronic health conditions, and this lessens dramatically as the years progress6.

This reduced resilience to some infectious diseases in older adults contributes to and compounds the ever-present pressures in the healthcare system each year, particularly when seasonal viruses are in circulation.

As such, one of the goals in vaccinating older adults is the prevention of these severe infections, thus avoiding hospitalisations after exposure to infection. This would serve to ease the burden of preventable diseases on health services – and the benefits of adult immunisation extend far beyond public healthcare.

Vaccine preventable diseases not only wreak havoc on our healthcare systems; they also affect the productivity of both those affected by disease and the friends and family who care for them.

Systemic review evidence from the UK suggests that 50% to 75% of employees miss work to provide care for family members suffering from influenza/influenza like illness annually7.

Studied across 10 countries, the OHE’s recent report on the Socio-Economic value of adult immunisation programmes, found that they offset their cost approximately 19 times over, equivalent to billions in net benefits to society8. In another study conducted in 2020, the return on investment for adult immunisation in high-income European countries was approximately €4 to every €1 spent9.

We are currently in the “Decade of Healthy Ageing”, a concerted effort by the World Health Organisation and the UN to combat the challenges faced by older adults. There are four key areas which the campaign aims to address; combatting ageism, introducing more age-friendly environments, and the consistent implementation of both long-term and integrated care for older people, the aim being to fundamentally change how we view and act towards ageing moving forward10. In Ireland, Minister for Finance Michael McGrath recently announced the “Future Ireland Fund” – A plan for future expenditure that addresses fiscal/economic issues such as ageing, climate, and digitisation in a sustainable and consistent way.

As we step closer to this Future Ireland, we must address the need that becomes more apparent every year for adult vaccination; an aging population requires a fast and effective health service, and that is unachievable with the burden of vaccine preventable diseases. The expansion of the National Immunisation Program to include a wider swathe of infectious diseases that affect adults will mitigate that burden. Adult immunisation should become a standard of care and should be regarded as a social responsibility for Governments and a cultural norm for citizens in the same ways as immunising children currently is.


  1. Andre FE; Bulletin of the World Health Organization;2008;86;140-146
  2. WHO (World Health Organization). (2024). Vaccines and immunization. Accessed May 2024. Retrieved from
  3. eurostat. (March 2021). More than a fifth of the EU population are aged 65 or over. Accessed May 2024. Retrieved from
  4. European Commission. (April 2024). The impact of demographic change in Europe. Accessed May 2024. Retrieved from
  5. Esposito S; The public health value of vaccination for seniors in Europe. Vaccine 2018;36;2523-2528
  6. Kenny et al. The Older Population of Ireland on the Eve of the COVID-19 Pandemic. TILDA. 2020. Retrieved from
  7. Zumofen, M.-H. B., Frimpter, J., & Hansen, S. A. (2023). Impact of Influenza and Influenza-Like Illness on Work Productivity Outcomes: A Systematic Literature Review. Pharmacoeconomics, 41(3):253-273.
  8. Office of Health Economics. 2024. Socio-Economic Value of Adult Immunisation Programmes. Retrieved from
  9. Bloom, D. E. (2020). Valuing Productive Non-market Activites of Older Adults in Europe and the US. De Economist, 168:153-181.
  10. WHO;2020;1-11;UN Decade of Healthy Ageing. Retrieved from