Disputed expertise and chaotic disinformation: COVID-19 and denialist physicians in Brazil.

This article aims to show how incorrect ideas about COVID-19 were promoted by physicians in Brazil, contributing to a catastrophic response at the cost of hundreds of thousands of lives, and to examine the implications of this episode for the social studies of science, technology and medicine. The literature on the relationship between science and society takes two broad approaches, which are sometimes at odds with each other: (i) there is a traditional critique of science that points to unsupported claims of certainty and thus undue interference in general human affairs; (ii) there are many examples of attempts to undermine reasonable scientific claims, when they clash with economic and/or political interests of certain groups. Navigating those extremes is particularly critical in situations in which accurate knowledge is necessary for intervening in people's lives, as is the case in health-related issues. Determining who has actual epistemic expertise is a key factor in solving this conundrum. This became painfully clear during the unfolding of the COVID-19 pandemic, which highlighted the uncertainties of science in guiding decisions being made in real time, and provided opportunities for many forms of disinformation and conspiracy theories that hampered public health measures and promoted useless or even dangerous "treatments". This article discusses an instructive example of such developments in the chaotic response to the pandemic challenge in Brazil, which saw, among other unfortunate situations, physicians aligned with the denialist federal government advocating for unproven - or proven as ineffective - treatments and disseminating unfounded doubts about vaccines. Presumed expertise on the basis of professional training clearly did not translate into actual expertise in the necessary domains to ascertain the validity of such claims and scientific advice was overridden by ideology.