A study by researchers at the University of Portsmouth in Vaccine at the end of October explored the effects of the COVID-19 pandemic on vaccine confidence. As we have previously explored, vaccine fatigue, vaccine hesitancy, and anti-vaccine disinformation have contributed to lower rates of vaccinations in certain populations. This recent study compares two cross-national surveys with “similar modalities” in 2019 and 2022 to explore changes in vaccine confidence and the links to “specific demographics”.  

How did we get here? 

Although “vaccination is widely considered to be one of the safest and most effective primary health care measures” it is a hugely contentious subject. In the face of historic successes, such as reductions in typhus, cholera, and plague, and more recent effects such as a “substantial drop in cervical cancer incidence”, large groups remain unsure of or opposed to vaccines.  

“Despite overwhelming evidence supporting its importance as a key primary prevention measure, immunisation has been the object of controversy and vocal opposition ever since its inception.”  

The authors consider “Wakefield’s infamous article” in 1998 and the “subsequent MMR controversy” but acknowledge that vaccine hesitancy and refusal have their origins in the “early days of variolation, even before the administration of the first vaccine”.  


The Strategic Advisory Group of Experts (SAGE) was established in 1999 by the WHO to “provide guidance” on its work. It is the “principal advisory group to WHO for vaccines and immunisation”. In 2011 it proposed the 3Cs Model as determinants of vaccine hesitancy: Confidence, Complacency, and Convenience. As we explore in our post in the 5C model, it has since been expanded by other sources, to include Calculation and Collective responsibility. SAGE frameworks contribute to global national health approaches and vaccination campaigns, most recently to “model hesitancy and refusal of COVID-19 vaccines”.  


The authors of the paper reflect that at the time they were writing, “11.9 billion doses” of a COVID-19 had been administered. This corresponds to “61.2% of the global population being” what is contentiously referred to as “fully vaccinated”. However, they do acknowledge “wide variation in vaccination rates” between countries.  

“While the rapid development and administration of COVID-19 vaccines are widely considered an extraordinary public health accomplishment, they also spurred considerable controversy and opposition.”  

The authors suggest that “confidence” factors seem to be “preponderant”. Misinformation about the safety of these vaccines was particularly problematic. Although there were demonstrated benefits to mass vaccination programmes, The Lancet published an article in 2021 stating that “willingness to vaccinate against COVID-19 has declined” between the “early months of the pandemic” and the end of 2020. Thus, this study aims to ascertain whether public vaccine confidence has fallen “below pre-pandemic levels despite the successful implementation and outcomes” of COVID-19 vaccinations.  

The study 

Two anonymous online surveys were carried out to “investigate the public perspectives on the practice of vaccination and the factors that might underpin hesitancy and refusal”. The first took place between November and December 2019, just as early cases of the virus were identified in China. The second was distributed in January and February 2022. The questionnaires were “adapted from the WHO SAGE Vaccine Hesitancy Scale”. Most importantly for this study, 10 questions were the same across the surveys.  

Overall, 1009 participants were recorded, with demographic “deviations”. However, “both cohorts showed a majority of female, white, young adults”. Within each cohort the study suggests “internal trends were relatively consistent”. Despite these, “irrespective of the participants’ gender, age, graduate status, ethnicity, and religious belief” there was a “decline in vaccine confidence scores following the COVID-19 pandemic”.  

“Only approximately 1 in 5 participants of the 2022 cohort self-assessed their vaccine confidence as having increased since the pandemic”.  

The implications  

Although the study is limited, with the lead author Dr Alessandro Siani suggesting to SkyNews it should be “interpreted with a grain of salt”, it does corroborate “other observations suggesting that vaccine confidence may be yet another victim of the COVID-19 pandemic”. Another limitation is the “use of a non-probability sampling strategy”, which means the cohorts were not necessarily “representative of the wider population”. With this in mind, “further investigations are required” to confirm the extent to which this observed reduction in confidence is “representative” of other populations.  

The authors conclude that across all demographic groups there was a reduction in confidence but state a “statistically significant association” between “Asian ethnic backgrounds and low vaccine confidence” among other trends. Overall, the general decrease in vaccine confidence implies a decrease in uptake for routine immunisations, childhood immunisations, and protection against future threats.  

For more on vaccine views at the World Vaccine Congress in Washington 2023 get your tickets now.