That Old Time Anti-Vaxx Feeling

The best single predictor of vaccine uptake per US state is not political affiliation, but the share of the population that believes the human race has always existed. Such findings do not bode well for the global effort to boost vaccination rates.

Crowd of people protesting against coronavirus vaccination.
Crowd of people protesting against coronavirus vaccination.


Vaccination is the best protection against COVID-19, and the evidence for that is overwhelming. While protection against infection or transmission is not guaranteed – especially with the Delta variant raging – getting vaccinated substantially reduces the risk of severe illness, hospitalization, and death from the coronavirus. Widespread vaccination is thus the key to enabling responsible governments to relax public-health restrictions, thereby allowing the economic recovery to continue. But this seems increasingly to be out of reach.

Researchers estimate that 70-85% of the population needs to be vaccinated (or otherwise immune to COVID-19) to end the pandemic. Yet even in Israel, which was leading the world in its vaccination drive at the beginning of 2021, the share of the population that has been vaccinated has stalled at just over 60%. In the United States, only about half the population is now protected, and vaccination rates have plummeted from 3.2 million doses per day in April to fewer than 700,000 doses per day as of early August.

The US case is particularly interesting, because the country-wide average obscures large differences among socio-economic groups and across states. Whereas over 63% of people in Massachusetts and Maine are fully vaccinated, only 34% of people in Mississippi and Alabama are. Across towns and counties, the disparities are even larger.

This is less a problem of access than of acceptance. It has been widely observed that, at least in the US, the willingness to be vaccinated is correlated with political affiliation. Polls show that only around 54% of Republican adults have been vaccinated, compared to 86% of Democrats. In counties that voted for Donald Trump, a Republican, in the 2020 presidential election, vaccination rates are more than ten percentage points lower than in counties that voted for Joe Biden, a Democrat.

But while the statistical link between political affiliation and vaccine hesitancy is strong, correlation does not equal causation. Moreover, anti-vaccine sentiment is nothing new: the NoVax movement existed long before the COVID-19 pandemic. The question, then, is whether people are refusing the COVID-19 vaccine merely because of their political beliefs, or whether those political beliefs and their stance on the vaccine reflect other, deeper factors.

A look at people’s broader attitudes toward science and trust in the establishment (scientific and otherwise) could help us to find the answer. One useful indicator here is the acceptance of evolution. Surveys have found repeatedly that a substantial minority of Americans reject the scientific consensus that humans are the product of a long process of natural selection.

Belief in evolution is strongly linked to acceptance of vaccination. Indeed, the best single predictor of vaccine uptake per US state is the share of the population that believes the human race has always existed.

Interestingly, religious beliefs do not seem to be decisive here. The link between vaccine uptake and the prevalence of the belief that divine intervention steered evolution is rather weak. Furthermore, political partisanship, as measured by voting patterns in the 2020 presidential election, loses its predictive power over vaccine uptake after one accounts for belief in evolution.

The implication is that attitudes toward vaccination are rooted not in party allegiance, but in a latent mistrust of science. This may reflect how democracy works more broadly. As Christopher H. Achen and Larry M. Bartels argue in their 2017 book, Democracy for Realists: Why Elections Do Not Produce Responsive Government, it is not that political parties present their programs, and rational voters choose which to support; instead, parties represent existing identity groups.

In the US, the Republican Party has positioned itself so that it captures the segment of Americans who do not accept science if its results collide with their worldview. This type of person does not believe in evolution (roughly one-quarter of the population, on average) and tends to reject COVID-19 vaccines. But the GOP is not necessarily responsible for those stances. So, contrary to Jeffrey Frankel’s recent , America’s Republicans probably cannot be said to be “killing their voters.”

In a sense, this is bad news. If people’s decision not to get vaccinated is based on fundamental beliefs, it will be much more difficult to change than if it was based on political partisanship or health concerns. Disseminating more factual information – more studies, more statistics – will not make a difference. After all, evolution has been taught in schools for generations.

Financial incentives, like lotteries, might sway some of the doubters. But a substantial community of hardcore anti-vaxxers is likely to remain – and not only in the US. Compulsory vaccination elsewhere, such as in France, is also being met with strong resistance. As the Delta variant fuels new COVID-19 outbreaks, governments in countries with a strong anti-vaxx movement have few good options left.


Daniel Gros is a member of the board and a distinguished fellow at the Centre for European Policy Studies. 


This article was first published by Project Syndicate on 6 August 2021. Copyright: Project Syndicate, 2019.