Vaccine hesitancy is a relatively new term for a phenomenon that is as old as vaccination itself. Defined by World Health Organisation as ‘delay in acceptance or refusal of vaccination despite availability of vaccination services,’ importantly it is ‘complex and context specific, varying across time, place and vaccines.’

Although this definition includes issues such as availability of and access to vaccines, in practice the term has become used to describe the expression of concerns and questions about vaccination. As the COVID-19 vaccination programme is being rolled out, it is an issue that is attracting much discussion in mainstream media, due to concerns that vaccine acceptance or intention to be vaccinated among some groups is less than optimal. It has been suggested that vaccine hesitancy is increasing, which in view of the proven value of vaccination is a great concern. Indeed, in 2019, WHO identified vaccine hesitancy to be one of the 10 threats to global health.

So, what is the extent and nature of vaccine hesitancy concerning the UK childhood vaccine programme? One important limitation in answering this question is that vaccine hesitancy is not routinely measured; several instruments have been developed but so far have only been used in studies. However, based on vaccine uptake figures, vaccine hesitancy appears to be low. Almost 93% of UK children receive a completed course of primary vaccines by 12 months of age, which increases to 95% by 24 months. Over 91% of two-year-olds receive a first dose of MMR vaccine, which increases to 95% by five years. This is supported by regular Public Health England surveys of parents with young children, in which over 90% of parents report automatically having their children vaccinated when due. So, turning the current issue on its head, vaccine confidence seems to be high in UK. However, it is also important to recognise that vaccine acceptance is not simply polarised into acceptance or refusal, rather it is on a continuum with some parents accepting vaccines while still having varying degrees of doubt and needing reassurance or further information from Health Care Practitioners (HCPs). We must not assume that a vaccinating parent has no questions or concerns. Only a small proportion of parents (about 1-2%) actually refuse all vaccines and it is a tiny proportion of the population who have the extreme views that can be considered ‘anti-vaxx’. Although this term is used liberally, particularly by the media, it is inaccurate and may be taken as insulting to most parents who voice concerns about vaccines to call them anti-vaxx. The power of the anti-vaxx movement is its loud voice and reach rather than its size, but for parents with genuine concerns it may be influential.

Importantly, although overall childhood vaccine uptake is very high, it varies between and within districts, with the lowest uptake in the UK in London. Where immunisation uptake is sub-optimal, it is obviously important to determine the reasons for this, rather than making assumptions. In a classic example, uptake of vaccination was noted to be poor among an orthodox Jewish community in north London with resultant regular outbreaks of measles. It had been suggested that parental religious beliefs might be among key reasons for this under immunisation. A detailed investigation revealed that their concerns were similar to those of the wider population, relating to vaccine safety or concerns about ‘vaccine overload’. A major barrier to vaccination for this community, where family size is often significantly larger than average, was the difficulty making vaccination appointments and long waiting times, with young children in an environment which was not family friendly, often cramped and with nowhere to leave prams.

Research consistently shows that low vaccine uptake in UK is associated with large family size, lone parents, mobile families, children having chronic or disabling health conditions for whom accessing services may be difficult, or not prioritised for practical or logistical reasons. Ensuring high vaccine uptake thus requires a combination of the provision of well organised, flexible, culturally appropriate and family friendly services, an ensured vaccine supply, information systems to monitor uptake as well as to facilitate a reminder and recall system for parents. Well informed, enthusiastic health professionals, who can respond appropriately and effectively to parents’ questions and concerns, can do much to provide reassurance and allay any fears around vaccination. Key to this is that parents tend to follow the advice of those they trust. Trust can be developed or increased through vaccine conversations in which parents are listened to, taken seriously and responded to openly and honestly. This is an important part of an effective vaccination service, particularly now with easy access to mis- and disinformation on social media.

Understandably, people have always hesitated around vaccination due to safety concerns. During the Whole Cell Pertussis Vaccine safety scare in 1970s and MMR vaccine controversy in the 1990s and 2000s, these became heightened, and concerns about the latter still persist to some extent. More recent additions to these are concerns about vaccine content such as aluminium and formaldehyde, animal derived content, or multiple vaccines overloading the immune system. The success of the vaccination programme, with vanishingly rare incidence of disease may contribute to enabling these to take hold. Balancing the risks of disease against the risks of vaccine (albeit very small) becomes difficult in the virtual absence of disease. However, even in the midst of a pandemic where vaccination represents the only viable way out, fears over the speed of development of COVID-19 vaccines using new technologies is causing some to question their safety and to hesitate over vaccination.

Although the childhood vaccine programme in the UK is very successful, with generally high uptake there is no room for complacency and considerable room for improving uptake in some parts of the country. While there is still a need to identify effective interventions to address vaccine hesitancy, improving access using established evidence-based good practice would go a long way to closing the immunisation uptake gap.