We have spent decades developing vaccines that can protect people from serious disease. They have undergone rigorous clinical trials, been approved by regulators and, in many cases, included in national immunisation programmes. But a vaccine can only protect someone if they actually get it.
That may sound obvious, but it is an important part of the vaccination journey that is easy to overlook. Much of the conversation understandably focuses on the science: which vaccines we need, how well they work and who should receive them. Far less attention is paid to what happens next. Developing an effective vaccine and running an effective vaccination programme are two different achievements.
Between recommendation and protection lies what we might call the last mile of vaccination. Booking an appointment, getting there, taking time away from work or caring responsibilities, understanding the recommendation, having confidence in the person giving it and, where necessary, coming back to complete the schedule. These practical details may seem mundane compared with the science behind a vaccine. In reality, they can determine whether that science ever translates into protection.
Timing isn’t about a calendar. It’s about protection.
Vaccination schedules aren’t arbitrary. The timing and spacing of doses reflect when people are most vulnerable to particular diseases, how the immune system responds at different ages and when further doses are needed to build or maintain protection. For babies and young children, delaying vaccination can therefore extend the period during which they remain susceptible to preventable disease.
But the principle doesn’t end with childhood. Increasingly, immunisation is being understood through a life-course lens: the protection we need changes as we move from infancy and adolescence through pregnancy, adulthood and older age. WHO’s Immunisation Agenda 2030 sets out an ambition for “everyone, everywhere, at every age” to benefit from vaccines. Some vaccinations establish protection early in life; others become relevant because our risks change, immunity may need reinforcing through booster doses, or new opportunities for prevention emerge as we age.
That matters increasingly as populations age. For the first time, adults over 65 now outnumber children under five globally, and the WHO estimates that nearly one billion people will be in this age group by 2030. WHO increasingly positions adult vaccination as part of healthy ageing, rather than something we largely complete in childhood.
The right protection matters. So does receiving it at the right time. A recent case in Italy is a stark reminder that diseases many people assume belong to the past have not disappeared. In August 2026, a four-year-old girl in Palermo who had reportedly not been vaccinated died following a probable case of diphtheria. A cousin of the same age also tested positive and was hospitalised. The full circumstances were still being investigated at the time of reporting, but the case is a sobering reminder of what can sit behind the clinical language of ‘vaccine-preventable disease’.
The schedule looks rather different from the kitchen table
On paper, an immunisation schedule can look straightforward. Now consider it from a parent’s perspective.
You have two children. You work shifts. The clinic isn’t nearby. An appointment means negotiating time off, arranging care for your other child and finding a way to get there. Then there is another appointment a few weeks or months later.
Perhaps you have questions too. You’ve seen something worrying online and aren’t sure whether it is true. You intend to ask a healthcare professional, but the appointment is short, your child is upset, and other patients are waiting. This is the point at which a well-designed health programme meets ordinary life. And ordinary life is messy.
The latest global figures show what is at stake. In 2025, 90% of infants worldwide, nearly 116 million children, received at least one dose of a vaccine protecting against diphtheria, tetanus and pertussis. But only 85%, around 110 million children, completed the three-dose series.
Behind every missed vaccination lies a unique set of circumstances, and there isn’t necessarily someone who decided against vaccination. A clinic may have been too far away. A day’s lost wages may have been unaffordable. An appointment might have been missed and never rearranged. Perhaps nobody explained clearly why another dose was needed.
An unvaccinated person is not necessarily a vaccine-hesitant person. Sometimes the barrier is belief. Sometimes it is a bus timetable.
That distinction matters because the solutions are completely different.
Convenience is more important than it sounds
Healthcare sometimes talks about convenience as though it were an added benefit. In prevention, it can be much more fundamental.
Every additional appointment creates another opportunity for life to interfere. That inconvenience is not distributed equally. For someone with a car, flexible working hours and a nearby clinic, another appointment may simply be irritating. For someone paid by the hour, living in a rural community, caring for several children or dependent on public transport, it can become a genuine barrier to healthcare.
WHO’s Behavioural and Social Drivers of Vaccination framework recognises that uptake is influenced by much more than attitudes towards vaccination. That matters because simplicity isn’t only about creating a better patient experience. It is also about access and, ultimately, equity. Making prevention overly complex risks placing the greatest burden on people who already face the greatest barriers to healthcare.
Why fewer injections and fewer journeys can matter
Combination vaccines offer a useful example. Rather than requiring a separate injection for every disease, they can provide protection against several diseases in a single injection.
Fewer injections have an obvious benefit for a child or parent, but they can also simplify the practical journey. Combination vaccines can reduce the number of injections and clinic visits and make recommended schedules easier to complete on time.
A recent independent systematic review also found some evidence of a potential benefit for vaccination timeliness, although the authors were clear that the quantity and quality of evidence remain limited.
Combination vaccines won’t solve every reason why vaccination is missed, and the evidence shouldn’t be stretched beyond what it shows. But the underlying principle matters: every unnecessary appointment or journey creates another opportunity for life to get in the way.
WHO has a useful term for part of this problem: a “missed opportunity for vaccination” when someone eligible for vaccination has contact with health services but leaves without receiving a vaccination they need.
That raises some simple questions. Could vaccination happen during another healthcare appointment? Would a reminder help? Could an appropriate community or pharmacy setting bring vaccination closer to the person who needs it? Are we asking people to make additional journeys when we don’t need to?
Availability and accessibility are not the same thing. A vaccine can technically be available while remaining remarkably difficult for some people to receive.
Information matters. But so does the conversation.
Removing practical barriers is only half the job. People also need to understand what is being recommended and why.
That has become more difficult in an environment where someone can encounter dozens of claims about vaccination on their phone before having a few minutes with a healthcare professional. Some will be accurate. Others won’t. Many will lack context, while the most alarming can often be the most memorable.
Simply providing more information isn’t necessarily the answer. A parent asking whether a vaccine is safe isn’t necessarily opposed to vaccination. They may simply be doing what parents do: trying to make the best decision for their child. An older person asking why they need a vaccine they have never previously been offered isn’t necessarily hesitant either. They may reasonably want someone to explain what has changed.
Treating every question as resistance is a good way to lose confidence. Good health communication shouldn’t mean telling people what to think. It means listening carefully enough to understand the question being asked, answering it clearly and credibly and giving people the information they need to make an informed decision.
That is why a few minutes with a doctor, nurse or pharmacist can matter so much. CDC guidance describes a strong healthcare professional recommendation as a powerful motivator for vaccination and reports that parents receiving such a recommendation are four to five times more likely to have their child receive HPV vaccination.
If we expect healthcare professionals to have those conversations, we need to equip them properly. They need current evidence and straightforward ways of explaining benefits and risks. They need to understand the questions people are encountering outside the consulting room. And, wherever possible, they need enough time to listen.
A leaflet can provide information. A good conversation can build confidence.
One message won’t work for everyone
Good communication also means recognising that vaccination decisions aren’t made under identical circumstances. The questions of a new parent are unlikely to be the same as those of an adolescent, a pregnant woman, a healthy 40-year-old or an 80-year-old managing several health conditions.
Nor should we assume that the same information, delivered in the same way, will work equally well across different communities, cultures or countries. Communication works best when it starts with the person rather than the message.
The objective shouldn’t simply be to tell people to vaccinate. It should help someone understand what protection may be appropriate for them, why it matters, when it is recommended, where they can receive it and what to expect. That makes communication part of the vaccination journey rather than something added afterwards.
Vaccination doesn’t end when childhood does
Ask someone to picture vaccination, and there is a good chance they will imagine a small child sitting on a parent’s knee. Yet infectious disease doesn’t stop when we turn 18, and neither does the value of prevention.
Pregnancy is perhaps one of the clearest examples of why protection needs to be considered across life. In England, vaccination against influenza, pertussis and RSV is recommended at different points during pregnancy. Maternal vaccination can protect the mother, while, for some infections, antibodies passed to the baby can provide protection during those first vulnerable months. It is a reminder that vaccination can sometimes protect across generations as well as across years.
Needs continue to change in adulthood. In the United States, for example, the CDC lowered the routine age-based recommendation for pneumococcal vaccination from 65 to 50 in 2024, giving more adults the opportunity to receive protection at an age when the risk of pneumococcal disease begins to increase.
Recommendations will differ across countries, but the broader point holds true. We cannot reasonably expect people to keep track of every change in the protection that may become relevant to them over a lifetime. Health systems and healthcare professionals have to create those opportunities.
Access also remains deeply unequal. Influenza vaccination for older adults is included in national immunisation schedules in 89% of high-income countries but only 8% of low-income countries. For pregnant women, the corresponding figures are 87% and just 4%.
That gap isn’t simply about whether a vaccine exists. It is about whether health systems have built prevention into the way they care for people at different stages of life.
Living longer is only part of the story
Living longer is one of modern medicine’s great achievements. But simply adding years isn’t enough. The more meaningful measure is how many of those years people can spend in good health, independent and engaged with the people and things that matter to them.
The International Longevity Centre UK’s Healthy Ageing and Prevention Index reflects that broader idea, looking beyond lifespan to include measures such as health span, work span and wellbeing. The underlying argument is an important one: longevity shouldn’t be judged only by how long people live, but by whether societies invest in prevention and create the conditions for people to live those longer lives well.
My FINN Partners colleague Mark Chataway has written about this through the lens of the “longevity economy” in an Ebook on shaping the future of global health. Many older people want to continue working and contributing but are prevented from doing so by poor health, he argues, while a significant proportion of that ill health could be prevented, treated or delayed with interventions available today.
That takes healthy ageing out of the abstract. Prevention, whether through vaccination, screening, nutrition, physical activity, appropriate treatment or access to good healthcare, isn’t simply about avoiding an episode of illness. It can help people remain independent, productive and part of their families and communities for longer.
WHO’s wider life-course approach points in a similar direction. Health shouldn’t be considered as a series of isolated episodes of illness, but something shaped throughout life, with opportunities to intervene at important moments from pregnancy and childhood through adulthood and older age.
For a child, prevention can mean fewer days away from school. For a parent, fewer days away from work caring for a sick child. During pregnancy, it can mean protecting a mother and helping protect a baby at the very beginning of life. For an adult, it can mean remaining healthy enough to work and care for others. For an older person, avoiding serious infection can help preserve health and independence.
Prevention isn’t an abstract health-system outcome. This is what it looks like in people’s lives.
Perhaps we need to ask a different question
There will always be important debates about which vaccines should be recommended, when they should be given and to whom. Those decisions must remain grounded in good science. But once we know how to prevent a disease, there is another question worth asking: How easy are we making it for people to act on that knowledge?
Can people access vaccination, understand why it matters and get credible answers to their questions? Does their healthcare professional have the information and confidence to explain it? Can they realistically complete the recommended schedule? And are our systems designed around people who already find healthcare easy to navigate, or are we thinking hard enough about those who face the greatest barriers? These aren’t secondary considerations. They are part of whether prevention works.
Developing better vaccines remains enormously important. But scientific innovation can only achieve so much on its own. The next challenge isn’t simply innovation in what we develop. It is an innovation in how effectively we deliver it.
We need to make the right protection easier to access, understand and complete at the right point in people’s lives, while giving parents, caregivers, patients and healthcare professionals the information and support they need along the way.
A vaccine sitting in a fridge is a scientific achievement. A vaccine reaching the person who needs it, when they need it, is a public health success.
That is the journey that matters.
