Global efforts must tackle complacency as coronavirus vaccines are rolled out to younger age groups, experts have said.

A five-pronged approach focused on the five C’s – confidence, complacency, convenience, communication and context – is needed to combat vaccine hesitancy, according to scientists from the UK, US and South Africa.

Writing in the Royal Society of Medicine journal, they say complacency due to lower perceptions of personal risk and disease severity, particularly among younger people and those of lower socioeconomic status, is strongly associated with lower vaccine uptake.

One of the authors, Dr Mohammad Razai, of the Population Health Research Institute at St George’s, University of London, said: “As the lower age groups are being offered the vaccine, addressing complacency through repeated risk communication is crucial to facilitate informed decision-making.

“It is important to emphasise the greater societal benefits of population level immunity and the protection it offers to those vulnerable, their families and friends.”

The proposed strategy also focuses on convenience of vaccination delivery, communication to combat misinformation, and recognition of context including ethnicity, religion, occupation and socioeconomic status.

Confidence in vaccine safety, efficacy and importance is crucial, and the public needs to be aware that for most people the benefits of vaccine “vastly outweigh the risk” of rare side effects, they write.

They say it is crucial to engage in transparent dialogue that “respects people’s concerns and acknowledges uncertainty”.

Author Professor Melinda Mills, Nuffield Professor of Demography and Director of the Leverhulme Centre for Demographic Science at Nuffield College and the University of Oxford, called for a “concerted international effort” to overcome hesitancy.

She said: “It is estimated that at least 60-70% of the world’s population needs to be vaccinated to achieve an effective herd immunity.

“However, European data show lower intention to be vaccinated amongst racial and ethnic minorities, those with lower education, younger people and people with previously poor compliance with recommended vaccinations.

“Covid-19 has exacerbated inequalities related to ethnicity and socioeconomic status and higher vaccine hesitancy in these groups could compound it even further.”