Key research papers on vaccine hesitancy

How the literature is organised

The oldest listed works are from 2013 to 2015. Dubé et al. (2013) gave an overview of the phenomenon and its causes. Larson et al. (2014) systematically reviewed determinants around the world for 2007 to 2012. MacDonald (2015) reports the SAGE Working Group's definition — delay in acceptance or refusal of vaccination despite availability of services — along with the complacency, convenience and confidence factors and the Vaccine Hesitancy Determinants Matrix, which sorts influences into contextual, individual and group, and vaccine-specific. Her paper also makes a point often lost in citation: low levels of hesitancy do not necessarily mean high vaccine demand. The same 2015 volume of Vaccine carried Jarrett et al.'s review of strategies. Earlier work used other vocabulary, such as vaccine refusal, so include it in searches that go back before 2010.

A monitoring literature runs alongside. Larson et al. (2016) surveyed 65,819 people in 67 countries and found sentiment positive overall but with the seven least confident countries out of ten in Europe, and 41% of French respondents disagreeing that vaccines are safe against a global average of 13%. De Figueiredo et al. (2020), pooling 290 surveys and 284,381 individuals across 149 countries, found confidence in the importance of vaccines the strongest single correlate of uptake.

Then came COVID-19: publication rose from 198 titles in 2019 to 1,683 in 2022, and all eight of the most-cited works since 2021 on this page are about COVID-19 vaccines, most of them national surveys.

Main debates

Three issues recur. First, what the word means. Aw et al. (2021), scoping 97 studies across high-income countries, found hesitancy rates ranging from 7% to 77.9% and concluded that the definitions used are so heterogeneous that the assessment needs standardising. MacDonald's own model includes convenience alongside confidence and complacency, and de Figueiredo et al. (2020) treat access as a persisting issue separate from trust — so a study that treats hesitancy purely as belief has narrowed the construct.

Second, the gap between intention and behaviour. Solís Arce et al. (2021) end by saying campaigns should focus on translating high stated acceptance into actual uptake, which is an admission that their own measure is not uptake. Schwarzinger et al. (2021) show how much the measure depends on what is asked: in a discrete-choice experiment with 1,942 French working-age adults, 28.8% refused a vaccine whatever its characteristics, while acceptance among the rest ranged from 27.4% for a vaccine of 50% efficacy manufactured in China to 61.3% for one of 90% efficacy manufactured in the EU.

Third, what works. Jarrett et al. (2015) found that only 14% of the peer-reviewed literature they reviewed had evaluated a strategy for impact, rated the evidence for social mobilisation, mass media, health-worker training, non-financial incentives and reminder systems as moderate quality, and concluded that multi-component and dialogue-based interventions were the most effective — while insisting that strategies be tailored to the population and its particular reasons for hesitancy.

Where recent work is heading

Trust in information sources is the correlate that recurs. Murphy et al. (2021) found hesitancy or resistance in 35% of a representative Irish sample and 31% of a UK one, with the resistant group less likely to get pandemic information from traditional and authoritative sources and similarly mistrustful of them in both countries. Robertson et al. (2021), in the UK household longitudinal study of 12,035 people, found overall hesitancy low at 18% but far higher in Black (71.8%) and Pakistani or Bangladeshi (42.3%) respondents, and Khubchandani et al. (2021) pooled 13 US studies to put hesitancy at 41.6% among African Americans and 30.2% among Hispanics against 26.3% overall. Those gaps, not the averages, are where the interesting questions are.

The evidence also now reaches settings that were thinly covered before: Solís Arce et al. (2021) across ten low- and middle-income countries, Soares et al. (2021) in Portugal, Schwarzinger et al. (2021) in France. For new research, whether pandemic-era hesitancy has spilled over into routine childhood immunisation is an open question where a student project with local data can contribute.