VACCINE hesitancy is a pressing issue of global concern, with the World Health Organization identifying vaccine hesitancy as one of the top 10 threats to global health in 2019.
Vaccines are one of the most successful and cost-effective public health interventions of all time, and yet, we are in a time when parents, in particular, seem to be questioning their safety and effectiveness more than ever. Vaccine preventable disease (VPD) outbreak reporting is presently dominating the global media, with grave concerns that many diseases thought to be close to eradication are returning in full force.
There has been a 31% increase in measles cases globally between 2016 and 2017. In 2018, measles cases in Europe soared to a 20-year high, with 72 deaths and over 80 000 people contracting the disease in 47 of 53 European countries.
As the WHO warns, pockets of low vaccine coverage in different countries and regions can readily erupt into disease outbreaks. For optimal disease prevention, rigorous monitoring and evaluation is urgently required to understand why populations are undervaccinated, design and implement effective interventions and identify trends in vaccine attitudes in different regions.
We know that vaccine refusal plays a clear role in VPD outbreaks, such as has been shown for measles and pertussis. However, it is important to recognise that vaccine hesitancy and refusal alone do not account for all these cases. Practical and programmatic issues also play a substantial role in low vaccine coverage. The nuance and complexity associated with this issue is often not portrayed by the media. Instead, the frequency of these outbreaks is often blamed on antivaccine information, spread online through social media, which causes parents to become fearful and refuse vaccines.
In fact, there are two main contributors to undervaccination: acceptance and access factors. The contribution of each varies between high, middle and low income countries and between different populations or cultural groups. Incomplete vaccination has been shown to be associated with many logistical factors, including family size, low parental education and missed opportunities or unnecessary delays in vaccine delivery.
For example, GPs or immunisation nurses may recommend a parent delay their child’s vaccines due to intercurrent illness, such as an upper respiratory infection with no fever, when this is not required. Other barriers include incomplete Australian Immunisation Register records, parents being unable to get time off work to attend immunisation sessions, or the financial and practical pressures facing families with many children. It has been estimated that only 3.3% of Australian parents are registered or unregistered vaccine refusers, leaving the bulk of the undervaccinated proportion of children due to these more logistical issues.
We urgently need to be able to accurately identify the relative contribution of each factor in areas affected by low coverage in order to tailor effective, evidenced-based solutions and use our limited resources and health dollars more wisely.
Despite relatively high vaccine coverage rates at present in Australia, with between 90.75% to 94.67% of 1-, 2- and 5-year-olds fully vaccinated, low coverage pockets still exist in every state in Australia and at both ends of the socio-economic spectrum. Furthermore, 2016 saw the removal of non-medical vaccine objection, which had served as a surrogate to monitor vaccine objection in the population. As a result, we now know less than ever before about the reasons for under- and non-vaccinated children in Australia. Most countries rely on vaccine coverage rates to monitor vaccination programs, but these are a very blunt instrument. Vaccination rates cannot tell us why specific people are undervaccinated or which provider communication approach might influence their decisions and behaviour. We cannot unpack how a multifaceted vaccine promotion intervention may operate or identify when confidence in vaccines is wavering and people may be susceptible to vaccine misinformation or scare campaigns. Importantly, vaccine coverage rates are also unable to provide information on timeliness and cannot distinguish between the key determinants of behaviour.
The WHO has recommended that every country develop strategies to “increase acceptance and demand for vaccination,” and has highlighted a pressing need for new tools that measure vaccine acceptance.
While vaccine acceptance measures have been developed for adolescents and for specific vaccines, only two measures of child vaccine acceptance have undergone validation. However, neither these nor any other available tool measures barriers to accessing vaccines, either alone or in combination with items measuring vaccine acceptance. As such, we currently lack the appropriate tools to “diagnose” all the causes of undervaccination in different settings where low vaccine coverage is a serious issue. In Australia, there is also no tool to enable regular national assessment of vaccine concerns or guide development of strategies to promote vaccine acceptance and uptake. For the most part, the measurement of the drivers of vaccine uptake is inconsistent and incomplete, resulting in limited evidence on effective strategies for different populations.
Supported by the National Health and Medical Research Council in 2018, our research team from the Murdoch Children’s Research Institute and the University of Melbourne, with key collaborators from the University of Sydney and the University of Newcastle and internationally, is developing the first comprehensive and interlinked model of parental acceptance and access barriers to childhood vaccination. The tool, named the Vaccine Barriers Assessment Tool or VBAT, will consist of a short and a long form.
The short form, likely featuring five questions, will be based on the most predictive and representative survey items and will be relevant for use in annual state-based or national health surveys to track vaccine attitudes over time. The long form (most likely 15 questions) will be relevant for evaluation of immunisation programs and interventions. It may also be used by local program delivery teams to improve uptake, or by clinicians to screen and diagnose barriers for individual parents and to guide more effective conversations to address their concerns.
The VBAT will be a validated tool that will draw on all known determinants of health behaviour to predict vaccine uptake. The tool will be developed in Australia using the COM-B framework to ensure all behavioural determinants of vaccine uptake are covered. The COM-B model has been used to explain and categorise barriers to vaccine uptake, according to (i) capability (knowledge about when and where to get a vaccine), (ii) opportunity (access to and social norms about vaccines) and (iii) motivation (attitudes and beliefs about vaccines). For the first time, the VBAT will allow identification of the key drivers of undervaccination in specific populations to guide the selection and implementation of cost-effective interventions to increase vaccine uptake. In the future, we anticipate that it will be adapted for use in low resource settings.
Once barriers have been accurately identified, the next step is to develop multicomponent interventions to target key time points and high-risk groups to improve vaccine uptake, including pregnant women, parents of young children and children who are medically at risk or have a disability, to name a few. The evidence is clear that such interventions should incorporate:
- structural levers at the systems level, with
- provider training in communication skills to further equip those at the front line to tackle the complexity of a conversation with a vaccine hesitant or refusing parent, and
- clear, easily accessible information that parents can trust to address their key vaccine safety concerns.
Parents don’t want motherhood statements that “all vaccines are safe and work,” they want the facts about vaccine safety, effectiveness and disease severity to be able to interpret the risks and benefits within their frame of reference and moral belief system. They need to be reminded of the severity of the diseases, without intimidation. Parents who have questions about vaccines and are “sitting on the fence” care deeply for their children and want to do the right thing but often remain conflicted and scared.
This is why the role of the trusted health care provider – the GP, midwife, paediatrician, obstetrician or adult physician – plays such a crucial role in building vaccine confidence and addressing vaccine safety concerns. Positive communication with a trusted health care provider and a recommendation to vaccinate is the most powerful predictor of vaccine acceptance, which explains why simply providing parents with more information on vaccines alone is not enough. Trust – in the government, health care providers and the health care system – is crucial to building vaccine-resilient communities that can weather the storm of vaccine safety scares and celebrity-driven antivaccine messages.
Billions of dollars fund the research and development of vaccines to ensure their efficacy and safety – now a serious investment in high quality vaccine communication science needs to be made to ensure sustained vaccine confidence. If we are to continue the global assault on VPDs and achieve the United Nations General Assembly Third Sustainable Development Goal to ensure healthy lives and promote wellbeing for all, it is essential that vaccine programs and research studies measure more than just uptake; we need valid and reliable instruments to measure and monitor people’s awareness, acceptance and access to vaccines to inform effective interventions.
Dr Margie Danchin is a clinician researcher and Team leader, Vaccine acceptance, Uptake and Policy, within the Department of Paediatrics, University of Melbourne and Murdoch Children’s Research Institute. Her research is focused on developing new interventions to improve vaccine confidence and uptake among different populations and in different settings and she is the lead investigator on the Vaccine Barriers Assessment tool funded by the National Health and Medical Research Council.
Jessica Kaufman is a post-doctoral researcher at the Murdoch Children’s Research Institute and the Centre for Health Communication and Participation (La Trobe University), and an Honorary Fellow of the University of Melbourne. Her current research projects include designing and testing new interventions to improve uptake and acceptance of maternal and childhood vaccines, vaccine program evaluation, and developing a database of instruments to measure vaccine-related attitudes, knowledge and decision making.
The statements or opinions expressed in this article reflect the views of the authors and do not represent the official policy of the AMA, the MJA or InSight+ unless that is so stated.