Despite the success of the COVID-19 vaccination campaigns, people's confidence in vaccines has declined significantly since the start of the pandemic, says a study.

Researchers from the University of Portsmouth in the UK investigated people's attitudes towards vaccinations and the factors that might underpin hesitancy and refusal.

By comparing the responses of more than 1,000 adults overall in two surveys, they found the post-pandemic group was considerably less confident in vaccines than in the pre-pandemic one.

The paper, published in the medical journal Vaccine, revealed nearly one in four participants reported a fall in confidence since 2020, and this was observed regardless of participants' age, gender, religious belief, education, and ethnicity.

"While vaccine hesitancy is not a new phenomenon, COVID-19 vaccines have been met with particular hostility despite the overwhelming scientific evidence of their safety and effectiveness," said Dr Alessandro Siani, associate head (students) of the School of Biological Sciences at the University of Portsmouth.

"This isn't just among conspiracy theorists though, but also those who don't consider themselves 'anti-vaxxers' and had supported other vaccination campaigns in the past," Siani added.

In both surveys, participants who held religious beliefs were significantly more vaccine-hesitant than atheist and agnostic ones, and individuals from  Asian backgrounds were more hesitant than those belonging to American ethnicities.

However, gender showed no association with vaccine confidence. While these overall trends remained largely similar between the two surveys, some noteworthy changes were observed in the post-pandemic survey.

For example, while in 2019 middle-aged participants were considerably more apprehensive about getting vaccinated than younger groups, this was not the case in the 2022 survey.

"This could be because COVID-19 infections notoriously lead to more severe outcomes in older patients," said Siani.

The study is consistent with other observations suggesting that vaccine confidence may be yet another victim of the COVID-19 pandemic, the researchers noted.