Political polarization drives surge in anti-vaccine legislation across the US

Despite overwhelming evidence on the safety and efficacy of COVID-19 vaccines, vaccine hesitancy intensified during the COVID-19 pandemic and has fueled skepticism towards other life-saving vaccines for children, adults, and pets.

A new study led by Boston University School of Public Health (BUSPH) researchers has revealed another worrying trend: the antivaccine sentiment once reserved for individual beliefs and public discourse has transformed into actual legislation across the US that could undermine vaccine uptake and pose a threat to the public's health. 

Published in the American Journal of Public Health, the study shows that proposed bills aiming to reduce vaccine access, weaken vaccination requirements, and increase vaccine exemptions increased dramatically in state legislatures from 2021-2023, at times exceeding the number of bills seeking to strengthen vaccine access and mandates. At least 40 percent of bills introduced in each full legislative cycle after the start of the pandemic have been antivaccine-related. 

Partisan polarization is clearly driving this legislation: Republican lawmakers sponsored 86 percent of the antivaccine bills introduced during this period. Democratic lawmakers, meanwhile, introduced 54 percent of provaccine bills, which are bills that supported an increase in 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 antivaccine bills introduced in recent years," says study corresponding author Dr. Matt Motta, who authored the study with Dr. Timothy Callaghan, both of whom are associate professors of health law, policy & management at BUSPH. "While the majority of these bills do not actually pass, it's important to remember that we live in an increasingly connected and globalized world-one in which low vaccine coverage in one part of the country can get people sick thousands of miles away. Weakening vaccine regulations in one state puts everyone's health at risk, as the current measles outbreak demonstrates."

Furthermore, a sizable amount of antivaccine legislation-24 percent-during this period did receive enough state legislative support to become law. Several states enacted laws that expand religious or personal belief exemptions for childcare and school immunizations, and measures that prohibit employers from mandating certain vaccinations in the workplace. 

"These antivaccine bills not only signal the discontent that some have with vaccines, but also the more hostile policy environments towards vaccination," Dr. Callaghan says. As the US approaches the November midterm elections, "who society chooses to elect in 2026 could shape vaccine policymaking for years to come," he says.

This analysis is the first to explore these partisan differences among vaccine-related bills proposed before and after the pandemic. For the study, Dr. Motta and Dr. Callaghan, along with a team of student and alumni researchers at BUSPH, systematically categorized partisan changes in 1,513 vaccine-related bills introduced in state legislatures between 2019-2023. The team utilized preliminary data of all vaccine-related proposed bills in state legislatures from 2019-2023 via the State Vaccine Policy Project (SVPP), a first-of-its-kind initiative created to understand and inform policies that address the politicization of public health. The SVPP is housed under The Politics and Health Lab that Dr. Motta and Dr. Callaghan direct at BUSPH. 

In 2021, a total of 1,154 vaccine-related bills were introduced in state legislatures, compared to just 386 proposed bills in the 2019 legislative session. Over the four-year period, nearly 82 percent of bills proposed by Democrats were provaccine, compared to less than 10 percent that were antivaccine. Comparatively, more than 65 percent of bills proposed by Republicans were antivaccine, compared to 28 percent that were provaccine. 

The spike in antivaccine legislation may be attributed in part to election-seeking GOP lawmakers who are eager to appease antivaccine Republican constituents who frame themselves as champions of medical freedom, individual autonomy, and parental rights, rather than opponents of vaccines. But health experts also emphasize that vaccine hesitancy is the result of the widespread misinformation, evolving public health guidelines, and broad distrust in science that has persisted in the US during and after the pandemic. 

"Nobody likes being told what to do. But our government has the ability and obligation to take actions that protect public health," says Dr. 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."

The team says their findings also underscore the importance of voter engagement in local elections and the need for continued efforts to improve communication about vaccines to the general public.

"We need to recognize that the reasons people lack trust in science are multifaceted, and that there isn't a one-size-fits-all solution that will work in restoring trust," Dr. Callaghan says. "We must also recognize that messengers matter as much, if not more, than the message. For public health, that also means recognizing 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 is currently severely underfunded."

In future research, the researchers intend to expand the SVPP dataset to analyze vaccine legislation over a larger period of time, as well as explore how public experiences with vaccination have shaped legislation and vice-versa. They will also examine health policies related to other subjects, including gender-affirming care, reproductive health, and water fluoridation.

"Our hope is to provide researchers with a large, up-to-date database cataloging 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 impacts public health," Dr. Motta says.