A decade on from the Northern Nigeria polio vaccination boycott and its global costs to the polio eradication initiative, a new report examines global issues affecting vaccine confidence and hesitation since the new millennium.
The State of Vaccine Confidence Report from researchers at the London School of Hygiene & Tropical Medicine (published 26 March) analyses some of the vaccine confidence issues that have occurred over the past decade with a range of vaccines, reports on strategies that have had positive impacts on engaging populations and building trust and confidence, and reflects on what still need to be learned.
The report also includes new research examining vaccine hesitancy rates in five countries (UK, India, Pakistan, Nigeria and Georgia) using a new Vaccine Confidence Index, which is the start of a global initiative to measure confidence in countries around the world.
These first findings from the Vaccine Confidence Index, also published in PLOS Current Outbreaks, reveal that while vaccine hesitancy and refusals are relatively rare, rates vary considerably between countries. The UK had the highest rate of parents hesitating when considering vaccinating their child (24.5%). Georgia had the highest proportion of hesitant parents going on to refuse vaccination at country level (60%).
At a state level in Nigeria the rate of refusal was highest in Kano state (74.2% of hesitant parents), which the researchers note reflects the a lasting effect of the 2003=04 polio vaccination boycott as Kano state was where the boycott persisted for eleven months.
Report lead author, Dr Heidi Larson, from the London School of Hygiene & Tropical Medicine, said: "Vaccine hesitancy is a highly varied, global challenge. Even small groups of hesitant or refusing individuals have the potential to severely undermine an immunisation programme. Public confidence is vital and our Vaccine Confidence Index will provide insights for policy makers and health professionals, to help them understand public sentiment about vaccinations, identify issues early, and act appropriately to ensure immunisation programmes are not disrupted."
Developed in collaboration between the London School of Hygiene & Tropical Medicine and the Global Public Health Polling Network (Gallup International), the Vaccine Confidence Index - a set of survey questions for parents of children under five years of age - will help detect waning confidence and address issues.
In the first set of surveys conducted in the UK, India, Pakistan, Nigeria and Georgia, 5,873 parents of children under five (under 15 in Georgia) were asked whether they had ever hesitated to vaccinate their children, and if so, whether they went on to accept or ultimately refuse vaccination. Reported reasons for hesitancy in all countries were classified as being due to either confidence (do not trust vaccine or provider), convenience (access) or complacency (do not perceive a need or value of vaccine). Issues of confidence were found to be the main reason for hesitancy in all countries surveyed.
The surveys will be expanded globally in the future to include more countries around the world, with results updated online and repeated over time. The report authors say it is imperative to global public health to understand the dynamics of vaccine confidence among the public, health providers and politicians or policy makers.
Developments in technology over recent years have meant dramatic changes in the ways and the speed in which information is shared. The internet has enabled like
inded people around the world to share their beliefs and concerns about vaccination, and means that both accurate and inaccurate information is readily available to anyone online.
Growing concern about vaccine hesitancy is reflected in the creation of new taskforces and research groups to examine the issue within organisations such as the World Health Organization Strategic Advisory Group of Experts on Immunization and the National Vaccines Advisory Committee in the US.
The report examines what strategies were successfully employed to overcome the challenges faced by immunisation programmes in different settings. The authors say that in many instances there is no single reason driving resistance to vaccination, understanding the influences behind confidence gaps is key to addressing them.
Dr Heidi Larson added: "Our new global mapping initiative places a finger on the pulse of public confidence in vaccines worldwide. Confidence in vaccines and immunisation programmes is a dynamic and changing phenomenon which influences behaviour and has consequences for the whole population. Reflecting on past experiences we can see just how much public trust matters. Without it, even the best science and public health strategies become powerless."
The researchers note that although the same core questions for participants were repeated across the five countries, the full set of questions posed in the survey was not precisely the same in every country. They also note that there was a mix of online, telephone and house-to-house (Nigeria) surveys used in the different country vaccine confidence studies. This means comparisons that can be made between countries are somewhat limited. However, there was a strong consistency in trends observed across most or all countries
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