Caregiver political affiliation is associated with childhood vaccine hesitancy but not fluoride opposition.

Political views, including one’s ideological beliefs and party affiliation, are an important potential determinant of a caregiver’s views on childhood disease prevention [1], [2]. Political ideology is a system of interrelated attitudes, beliefs, and values that shape how individuals interpret social and political information [3]. It can influence one’s values, identity, and party affiliation [3]. Party affiliation, also known as political affiliation, is the party an individual identifies with, endorses, campaigns for, and for which they vote [3]. Left-leaning individuals — often referred to as liberals and in the U.S. commonly associated with the Democratic Party— tend to value equality, progressive change, and relinquishing some personal liberties for the common good. Right-leaning individuals —often referred to as conservatives and in the U.S. commonly associated with the Republican Party — value tradition, hierarchy, and personal responsibility, supporting policies that emphasize individual agency [3].

Populist movements have shaped public attitudes toward vaccination [1], [2]. Public health policies enacted during the recent COVID-19 pandemic fueled medical populism by introducing public controversies over vaccine mandates, loss of employment because of an individual’s decision not to vaccinate, and not being allowed in public spaces without a facemask or vaccine verification [4], [5], [6]. Populism is a thin-centered ideology, focusing on a limited set of core ideas rather than providing a comprehensive political worldview, and is often combined with broader political and more complete ideologies. It divides society into the “pure people” versus the “corrupt elite” and is driven by the belief that politics should express the general will of the people [7]. Right-leaning populist movements have fostered skepticism toward health providers, scientific experts, and evidence-based policies – including widely supported preventive care like vaccines and public health measures like community water fluoridation (CWF) – by undermining public trust in institutions and science, although similar threats to preventive care are present across the political spectrum [5], [8]. One specific consequence has been a reduction in childhood vaccination rates. In Brazil, childhood vaccination rates declined after the 2016 impeachment of left-leaning President Dilma Rousseff — a process widely viewed as being driven by right-leaning political forces [9] — and dropped further following the 2018 election of far-right President Jair Bolsonaro [10]. Similar events are occurring in the U.S. and have been documented globally [11], [12].

Politically-influenced threats to preventive care have also affected dentistry and are not new. Concerns about fluoride – which helps prevent tooth decay or cavities – began in the 1950s, with unsubstantiated claims by the Birch Society that CWF was a Communist plot to achieve population-level mind control [13]. In the 1970s and 1980s, concerns about fluoride led to the discontinuation of CWF in Denmark, Sweden, the Netherlands, Germany, and Finland [14]. Similar concerns about CWF have been documented in Australia and Canada [15], [16]. Over time, these CWF-related concerns have spread to other forms of fluoride, including the topical fluoride provided by dentists during dental checkups and physicians during well-child visits [17]. U.S. dentists and physicians have reported increasing prevalence of topical fluoride hesitancy among caregivers of children [18], [19]. Recent right-leaning populist discourse in the U.S. has taken advantage of these historical concerns and further amplified them at the population level, leading to some initial policy successes. In 2025, the Utah and Florida legislatures banned CWF [20], prompted in part by anti-fluoride comments made by the U.S. Health and Human Services Secretary that were eventually codified as part of the current Administration’s Make America Health Again (MAHA) initiative [21]. Although unsuccessful, the U.S. Food and Drug Administration recently attempted to remove prescription fluorides from the market [22].

Past work has explored the link between political affiliation and vaccine hesitancy [5], [23], but the association between political affiliation and fluoride opposition is unknown. In this study, we test the hypothesis that conservative (right-leaning) caregivers are more likely to be hesitant about childhood vaccines as well as more likely to be opposed to topical fluoride and CWF than liberal (left-leaning) caregivers. This work is an important continuation of the nascent but growing interest in the political determinants of child health outcomes [24].