A July 2023 report by IQVIA Institute for Human Data Science, in collaboration with GSK and the Global Coalition on Ageing (GCOA), explores global adult vaccination trends with a particular interest in the consequences of the COVID-19 pandemic. The data suggest that, excluding COVID-19 vaccines, approximately 100 million fewer doses were administered in 2021 and 2022 than anticipated. This anticipation was based on trends from 2013 to 2020.

We have spent a lot of time recently exploring childhood immunisation rates, which have seen a tragic decline during the pandemic and are gradually recovering. However, IQVIA states that “despite the clear benefits” of adult immunisation, vaccination coverage is “always much lower in adults” than in paediatric programmes. Thus, this research offers a useful insight into trends and variations.  

Ageing populations 

IQVIA suggests that by 2030 the number of people aged 60 years and older is predicted to increase by over a third, to 1.4 billion. Furthermore, according to WHO, between 2020 and 2050 the number of people older than 80 is expected to triple to reach 426 million. This shift in population distribution is indicative of strengthened health systems but consequently places greater pressure on those health systems

From 2021 to 2030 the UN Decade of Healthy Ageing seeks to “reduce health inequities” and “improve the lives of older people” and their communities through “collective action”. Part of this action involves adequate primary health services and integrated personal care. One of the most cost-effective preventative measures that we have in our armoury is adult immunisation, which accrues returns on investment at “individual, healthcare system, economic, societal, and political levels”. It is therefore of great importance that adult immunisation rates stabilise and trend upwards.  

Vaccine-preventable pressures 

The report states that vaccine-preventable diseases (VPDs) impose a “significant burden” from economic and healthcare perspectives. The authors refer to WHO estimations: seasonal influenza epidemics alone lead to 3-5 million hospitalisations and 290,000-650,000 deaths. In the EU, VPDs cause “an estimated 94,000 premature deaths annually” with an associated “substantial” number of hospitalisations. They also increase the risks of health complications, compounding the economic and healthcare burdens.  

What did COVID-19 teach us? 

The COVID-19 pandemic “underscored the critical link” between health and the economy. We know from speaker David Humphreys that a “healthy population is a productive population”, and the total future lost earning from the pandemic is believed to be more than $10 trillion. However, there were positive lessons from the pandemic; the accelerated development and deployment of COVID-19 vaccines resulted in more than 72% of the global population receiving a dose. This “facilitated socioeconomic recovery” and, possibly more significantly, demonstrated that “prevention can be prioritised if all stakeholders work together”.  

COVID-19’s consequences 

Data from the past decade indicate “continual progress” in terms of volume of use of adult vaccines for influenza, TDaP, hepatitis B, herpes zoster, and pneumococcal. This reached a “historical” peak of around 400 million doses in 2020.  

“While the progress in adult vaccination between 2013 and 2019 is commendable, overall levels of vaccine coverage for adults have still remained low, which suggests that there is a need for further improvements.” 

However, despite the developments noted in the report, the growth associated with these vaccine doses was “adversely” affected by the COVID-19 pandemic. The overall doses reduced 12% between 2020 and 2022, to 351 million. Furthermore, there are “clear difference” in trends across countries at “different levels of human development”. The Human Development Index (HDI) is a composite measure considering life expectancy, education, and per capita income. 

Countries at the top end of the HDI scale had demonstrated the most positive trends in vaccine volumes pre-pandemic. After a pandemic decline, they seem to be “in the process of recovering”. “Medium” and “Low” HDI countries witnessed “substantial declines” in vaccination and have “not recovered”; doses remain “well below the historic trendlines”.  


The final consideration in the report is spending on adult vaccines, which “represents a minor share” of the wider pharmaceutical expenditure

“Even in the most developed regions, adult vaccine spend only amounts to less than 2% of total pharmaceutical expenditure.” 

In some regions, for example Europe and North America, there has been a “moderate increase” of 0.2-0.5 percentage points. However, in other regions the proportion is much lower, suggesting a “greater need for focus and potential investment” in adult vaccination. This is particularly important for developing countries that are seeing the fastest increase in adult populations.  

Policy implications 
“Adult immunisation not only prevents diseases, hospitalisations, and premature deaths, but also provides a wider individual and societal economic benefit.” 

In addition, vaccines contribute to the fight against antimicrobial resistance (AMR), which is a growing threat, particularly in under-resourced areas. Thanks to the significance of adult immunisation, “more than 80% of the vaccines in development target adults”. Unfortunately, access and uptake disparities exist within and across countries, but the extent of these is poorly understood. The report calls for future efforts to improve this, allowing for “more evidence-based policy”.  

“There is an urgent need for action to ensure that the adult vaccination trajectory is further enhanced through continued prioritisation and investments to chart a new course for healthier, more resilient societies across the globe.” 

The authors suggest that the following approaches might be useful to support optimisation of adult vaccination and capitalise on the “substantial progress” made during the pandemic to “raise awareness of adult vaccination” and “deploy policies to realise high vaccine uptake”: 

  • Make adult immunisation a standard of care. 
  • Increase the number of vaccinators. 
  • Capture and report vaccination data. 
  • Encourage, support, and incentivise HCPs. 
  • Raise media and public awareness.  
Working together 

Commenting on the report, GSK’s VP Global Vaccines Medical Affairs Piyali Mukherjee said that “significant strides in vaccine development” have enabled many adults to live longer, but the data show that “we are falling short”.  

“We are committed to collaborating with GCOA, IQVIA, and other experts, advocates, and communities to ensure more adults can readily access vaccination programmes.”  

Michael W. Hodin, GCOA’s CEO, agreed that adult vaccinations must be framed as “not only valuable for adult health but also for society”.  

“The health of our adult population is a critical factor in the overarching health of our global economy, and thus, prevention is a tool of positive impact for health systems overall.” 

We will be exploring adult immunisation programmes at the World Vaccine Congress in Barcelona this October, with a dedicated closing plenary on the future of adult immunisation. Get your tickets to join us here, and don’t forget to subscribe to our newsletter for more like this.