After the UK had been in lockdown for six weeks, we conducted, with a reputable market research company, a survey over one week of 2500 adults in England, representative for age, gender, income, and region (Freeman et al., Reference Freeman, Waite, Rosebrock, Petit, Causier, East and Lambe2020). Our view was that the epidemic contained all the necessary elements for conspiracy beliefs to flourish. The survey found appreciable endorsement of coronavirus conspiracy beliefs. Importantly, conspiracy thinking was associated with less adherence to social distancing guidelines and less willingness to be vaccinated. We believe this is important information for the public health response.

We welcome the chance to respond to the letter (McManus, D’Ardenne, & Wessely, Reference McManus, D’Ardenne and Wessely2020). First, the letter states ‘20% of the sample were children’. We would like to be very clear: the sample was of adults (18+ years old). The survey did not include any children. (We presume the confusion is due to reference in the paper to Office of National Statistics data on the general age composition of the UK population from which the adult quotas were derived.) Second, invited respondents did not know the topic of the survey before saying that they would complete it. They were simply told that there was a new survey and the time period for it to be completed. Only after agreeing to participate did they see the online introduction, which, in our opinion, is neutral, but it is presented in the paper for readers to form their own conclusion. We'd be surprised if it influenced the results. Only 111 individuals did not complete the survey after their initial (blinded) agreement, which would not have significantly altered the results. Third, it is indeed the case that approximately a fifth blamed Jews, a fifth blamed Muslims, a fifth blamed Bill Gates and so on, but as highlighted in the paper throughout, these are not separate fifths of the population but a proportion of the population showing a conspiracy mentality, which includes endorsing contradictory views. This endorsement style is a standard finding in conspiracy theory research (Wood, Douglas, & Sutton, Reference Wood, Douglas and Sutton2012). Put another way, our scale produced a single factor of specific conspiracy thinking, despite the variation in individual item content. The rating scale was chosen because the explicit focus of the survey was on tapping this conspiracy mentality in order to test associations with adherence to coronavirus guidelines. We deliberately presented unfounded, extreme beliefs (e.g. ‘The coronavirus vaccine will contain microchips to control the people’) to test whether there was any degree of endorsement (do not agree, agree a little, agree moderately, agree a lot, agree completely). The item content, not the scale, seems to us to merit the real focus. Which brings us to the last issue, which is the letter writers' concern about the news headlines. The university press release was titled: ‘Conspiracy Beliefs Reduce the Following of Government Coronavirus Guidance’. The text did include a few specific beliefs, such as this example: Jews have created the virus to collapse the economy for financial gain, 80.8% did not agree, 5.3% agreed a little, 6.8% agreed moderately, 4.6% agreed a lot, and 2.4% agreed completely. We do not consider this a sensationalist presentation.

Just because the results are surprising to some – but certainly not to many others – does not make them inaccurate. We need further work on the topic and there is clearly enough from the survey estimates to warrant that. Given the seriousness of what is at stake, both for the current crisis and more broadly, we should beware of ignoring uncomfortable possible truths.