Assessing the influence of French vaccine critics during the two first years of the COVID-19 pandemic.

When the threat of COVID-19 became widely acknowledged, many hoped that this pandemic would squash "the anti-vaccine movement". However, when vaccines started arriving in rich countries at the end of 2020, it appeared that vaccine hesitancy might be an issue even in the context of this major pandemic. Does it mean that the mobilization of vaccine-critical activists on social media is one of the main causes of this reticence to vaccinate against COVID-19? In this paper, we wish to contribute to current work on vaccine hesitancy during the COVID-19 pandemic by looking at one of the many mechanisms which can cause reticence towards vaccines: the capacity of vaccine-critical activists to influence a wider public on social media. We analyze the evolution of debates over the COVID-19 vaccine on the French Twittosphere, during two first years of the pandemic, with a particular attention to the spreading capacity of vaccine-critical websites. We address two main questions: 1) Did vaccine-critical contents gain ground during this period? 2) Who were the main actors in the diffusion of these contents? While debates over vaccines experienced a tremendous surge during this period, the share of vaccine-critical contents in these debates remains stable except for a limited number of short periods associated with specific events. Secondly, analyzing the community structure of the re-tweets hyper-graph, we reconstruct the mesoscale structure of the information flows, identifying and characterizing the major communities of users. We analyze their role in the information ecosystem: the largest right-wing community has a typical echo-chamber behavior collecting all the vaccine-critical tweets from outside and recirculating it inside the community. The smaller left-wing community is less permeable to vaccine-critical contents but, has a large capacity to spread it once adopted.

Does the public know when a scientific controversy is over? Public perceptions of hydroxychloroquine in France between April 2020 and June 2021.

OBJECTIVES: In the early stages of the coronavirus disease 2019 (COVID-19) pandemic, chloroquine and its derivatives such as hydroxychloroquine (HCQ) were widely commented upon both within the scientific community and in the media. This paper explores the different factors that influenced public perceptions in France of the efficacy of HCQ as well as their evolution between April 2020 and June 2021. METHODS: This article draws on 5 surveys conducted among representative samples of the French population (projects COCONEL and TRACTRUST; quota method, n=1006; 1004; 2006; 1014 and 1005). We asked questions on the effectiveness of chloroquine against COVID-19. We also collected sociodemographic variables and attitudes toward politics and science. RESULTS: Between April and June 2021, the proportion of respondents who believed in the efficacy of HCQ decreased rapidly from 35% to 14%. The proportion of respondents who believed that HCQ is ineffective rose gradually from 6% to 21%. After adjusting for the temporal effect, the logistic regression showed a very strong association between political orientation and the belief in the efficacy of HCQ. Respondents who felt closest to the more radical parties (far-right and far-left) were more likely to believe in the efficacy of HCQ than those who felt closest to the political center (O.R. 2.48 [1.95-3.15] and 1.87 [1.44-2.43]). The role of trust in the government and in science and of the degree of political engagement were investigated in the two waves conducted after the scientific consensus was established during the summer of 2020. High levels of trust in the government and in science and of politicization are associated with belief of HCQ proven inefficacy. Across the whole period, a majority of respondents were uncertain. Even in 2021, 41.5% stated that the data were insufficient to decide whether or not HCQ is effective and 25.2% stating that they did not know. CONCLUSION: Because media coverage of scientific controversies is higher in times of uncertainty than after these controversies have died down, the publicization of therapeutic promises can have lasting consequences on attitudes towards science and medicine.

French Public Familiarity and Attitudes toward Clinical Research during the COVID-19 Pandemic.

The COVID-19 pandemic put clinical research in the media spotlight globally. This article proposes a first measure of familiarity with and attitude toward clinical research in France. Drawing from the "Health Literacy Survey 2019" (HLS19) conducted online between 27 May and 5 June 2020 on a sample of the French adult population (N = 1003), we show that a significant proportion of the French population claimed some familiarity with clinical trials (64.8%) and had positive attitudes (72%) toward them. One of the important findings of this study is that positive attitudes toward clinical research exist side by side with a strong distancing from the pharmaceutical industry. While respondents acknowledged that the pharmaceutical industry plays an important role in clinical research (68.3%), only one-quarter indicated that they trust the industry (25.7%). Positive attitudes toward clinical trials were associated with familiarity with clinical trials (Odds Ratio, OR 2.97 [1.90-4.63]), financial difficulties (OR 0.63 [0.46-0.85]), as well as mistrust of doctors (0.48 [0.27-0.85]) and of scientists (OR 0.62 [0.38-0.99]). Although the French media provided a great deal of information on how clinical research works during the first months of the pandemic, there remains profound mistrust of the pharmaceutical industry in France. This suspicion can undermine crisis management, especially in the areas of vaccine development and preparation for future pandemics.

Potential lethal outbreak of coronavirus disease (COVID-19) among the elderly in retirement homes and long-term facilities, France, March 2020.

Motivated by the potential devastating effect of a COVID-19 outbreak in retirement homes and long-term facilities for dependent elderly, we present the impact of worst-case scenarios in French institutions using a specific age structure and case-age fatality ratios. The death toll could equal the yearly death toll caused by seasonal influenza in those older than 65 years or could largely exceed that, depending on the final attack rate and proportion of infected institutions.