Anti-vaccine bills surge in many states of the USA as Republicans drive legislation

Research from Boston University School of Public Health finds anti-vaccine legislation has risen sharply in state legislatures across the USA since 2021 with Republican lawmakers behind the majority of bills

A study led by researchers at Boston University School of Public Health, Boston, Massachusetts, USA, has found that legislation aimed at undermining requirements for individuals to be vaccinated has risen sharply across the USA since the start of the COVID-19 pandemic, with Republican lawmakers responsible for the overwhelming majority of such bills.

The research examined 1,513 vaccine-related bills that had been introduced into state legislatures between 2019 and 2023. It found that proposals designed to reduce vaccine access, weaken vaccination requirements or expand exemptions increased markedly from 2021 onwards, at times outnumbering bills that sought to strengthen vaccine access and mandates. Remarkably, at least two-fifths of all bills introduced in each full legislative cycle since the pandemic began have been anti-vaccine in nature.

The analysis attributed this shift largely to partisan polarisation. Republican lawmakers sponsored 86 per cent of the anti-vaccine bills introduced during the period. By contrast Democratic lawmakers introduced 54 per cent of pro-vaccine bills – which can be characterised as those seeking to expand access to, or funding and promotion of, vaccines across state legislatures.

“Our work shows that state lawmakers affiliated with the Republican party are responsible for the overwhelming majority of anti-vaccine bills introduced in recent years,” said Dr Matt Motta, corresponding author of the study and associate professor of health law, policy and management at Boston University School of Public Health, who conducted the research with Dr Timothy Callaghan, also an associate professor in the same department.

“While the majority of these bills [did] not actually pass, it is important to remember that we live in an increasingly connected and globalised world, one in which low vaccine coverage in one part of the country [means] people [can get] sick thousands of miles away.

“Weakening vaccine regulations in one state puts everyone’s health at risk, as the current [ongoing] measles outbreak demonstrates,” Motta added.

Around a quarter of anti-vaccine legislation introduced during the period has gone on to receive enough legislative support to become law. Several states have enacted measures that expand religious or personal belief exemptions for childcare and school immunisation requirements, along with laws that prevent employers from mandating certain vaccinations in the workplace.

“These anti-vaccine bills not only signal the discontent that some have with vaccines but also the more hostile policy environments towards vaccination,” said Callaghan. He added that, as the USA approaches its November midterm elections cycle, the outcome could shape vaccine policymaking for years to come.

The study is understood to be the first to explore partisan differences in vaccine-related legislation both before and after the pandemic. To conduct the analysis, Motta and Callaghan worked with a team of student and alumni researchers at Boston University School of Public Health to categorise partisan changes across the full sample of bills.

The team drew on preliminary data from the State Vaccine Policy Project, a first-of-its-kind initiative established to help researchers understand and inform policy responses to the politicisation of public health. The project operates under the Politics and Health Lab, which Motta and Callaghan direct at the university.

The scale of the shift is stark showing that in 2021, state legislatures introduced 1,154 vaccine-related bills, compared with just 386 in the 2019 legislative session. Across the full four-year period, nearly 82 per cent of bills proposed by Democratic lawmakers were pro-vaccine, compared with fewer than 10 per cent that were anti-vaccine. Among Republican-sponsored bills, the pattern was sharply reversed with more than 65 per cent being anti-vaccine in nature, compared with 28 per cent that were pro-vaccine.

Researchers have suggested that the rise in anti-vaccine legislation may partly reflect efforts by Republican lawmakers seeking re-election to appeal to anti-vaccine constituents, many of whom frame their position not as opposition to vaccines but as a defence of medical freedom, individual autonomy and parental rights. However, health experts also point to broader causes, including widespread promotion of misinformation with the online space of particular note. Also the evolving nature public health guidance can cause confusion and therefore doubt alongside the trend of a persistent decline in public trust in science since the pandemic.

“Nobody likes being told what to do. But our government has the ability and obligation to take actions that protect public health,” said Motta.

“To the many people who ground their opposition to vaccination in deeply held values, political views, religious beliefs and more, I would say: ‘Infectious disease has no sense of morality or religious creed.’

“Taking action to protect yourself and others is one of the safest and most effective actions you can take to live your life the way you want it. Vaccination is a way to take your freedom back from the pathogens that have caused sickness and death for all of human history,” he added.

The research team said its findings underline the importance of voter engagement in local elections, as well as the need for continued efforts to improve public communication about vaccines.

“We need to recognise that the reasons people lack trust in science are multifaceted, and that there is not a one-size-fits-all solution that will work in restoring trust,” said Callaghan.

“We must also recognise that messengers matter as much – if not more – than the message. For public health, that also means recognising that public health officials are not always going to be the right messengers to encourage vaccine uptake.

“Identifying the correct messages and messengers will take considerable investment in vaccine communication research which [has become] severely underfunded,” he explained.

The researchers intend to expand the State Vaccine Policy Project dataset to analyse vaccine-related legislation over a longer period, and to explore how public experiences of vaccination have shaped policy, and vice versa. Future work will also examine legislative activity in related areas of health policy, including gender-affirming care, reproductive health and water fluoridation.

“Our hope is to provide researchers with a large, up-to-date database cataloguing health policy legislative activity across the states, so that we can study how changes in our social and political worlds impact health policy, and how changes in health policy impact public health,” concluded Motta.

For further reading please visit: 10.2105/AJPH.2026.308535