Policy-makers had to strike a careful balance between restricting the hard-won personal freedoms of citizens to ensure the effectiveness of their policies and maintaining their support over extended periods in doing so - at times a carrot and stick approach.

Overcoming vaccine hesitancy to ensure widespread public take-up was especially important and was among the areas where governments leaned towards more stringent policy, with measures including mandatory jabs for certain job roles, and for international travel.

Such coercive policy was at times controversial but are the public at large actually supportive of such measures?

According to a new study published by a team of academics, they are…as long as the policy is effective.

In a paper published in the journal Scientific Reports, researchers found the public is willing to support stringent government policies that place restrictions or impose penalties upon them as long as the behaviour being encouraged is shown to be effective.

That support increases in line with the effectiveness of the encouraged behaviour but only up until a certain threshold, at which point it plateaus.

Data for the two-part study, which was focussed on hypothetical booster jabs, was drawn from more than 40,000 survey responses across seven nations, including the UK, US, Japan, Italy, Germany, France, and Canada.

The experiment in the first study described the effectiveness of the hypothetical booster as 50 per cent, 60 per cent, 70 per cent, 80 per cent, or 90 per cent. The experiment in the second study tested an alternative framing by presenting the effectiveness of the hypothetical vaccine in relative terms— “less effective,” “as effective,” or “more effective” than previous COVID-19 vaccines.

After receiving information about the effectiveness of the vaccine, survey respondents were then asked whether they would support a series of policies the government could use to encourage greater uptake that ranged from less stringent (freely available boosters) to more stringent (restrictions on accessing public spaces for the unvaccinated, employer mandates for the booster, fines for the unvaccinated, and tax breaks for the vaccinated).

Across both studies, researchers found the public was more willing to support stringent policies when the booster’s effectiveness was greater.

However, the study found no significant increase in support for more stringent policies when booster effectiveness was above 70 per cent in the first study or “more effective” than previous vaccines in the second – an unexpected finding for the research team.

Study author, Manu Savani, of Brunel University London, said: “The reasons for this unanticipated finding are an important topic for future research. It is possible, for instance, that people reached a ceiling on the level of stringency that they were willing to accept; or that the trade-off between policy benefits and limits to individual freedom is less compelling as policy effectiveness increases above some level.”

The researchers said the findings had direct implications for policymakers, health professionals and communicators.

The study was co-authored by Professor Peter John, Richard Koenig, and Andrew Hunter from the Department of Political Economy at King’s College London, with Manu Manthri Savani (Brunel University), Blake Lee-Whiting (University of Toronto), John McAndrews (McMaster University), Sanchayan Banerjee (Vrije Universiteit Amsterdam), Peter John Loewen (University of Toronto), and Brendan Nyhan (Dartmouth College).