Negative consequences of failing to communicate uncertainties during a pandemic: an online randomised controlled trial on COVID-19 vaccines.

OBJECTIVE

To examine the impact of the government communicating uncertainties relating to COVID-19 vaccine effectiveness on vaccination intention and trust after people are exposed to conflicting information.

DESIGN

Experimental design where participants were randomly allocated to one of two groups.

SETTING

Online.

PARTICIPANTS

328 adults from a UK research panel.

INTERVENTION

Participants received either certain or uncertain communications from a government representative about COVID-19 vaccine effectiveness, before receiving conflicting information about effectiveness.

MAIN OUTCOME MEASURES

Vaccination intention and trust in government.

RESULTS

Compared with those who received the uncertain announcement from the government, participants who received the certain announcement reported a greater loss of vaccination intention (d0.34, 95% CI (0.12 to 0.56), p=0.002) and trust (d0.34, 95% CI (0.12 to 0.56), p=0.002) after receiving conflicting information.

CONCLUSIONS

Communicating with certainty about COVID-19 vaccines reduces vaccination intention and trust if conflicting information arises, whereas communicating uncertainties can protect people from the negative impact of exposure to conflicting information. There are likely to be other factors affecting vaccine intentions, which we do not account for in this study.

TRIAL REGISTRATION NUMBER

Open Science Framework: https://osf.io/c73px/.