The Real Reason Behind Conservatives’ Shifting Views on Childhood Vaccines

In a new study released by Pew Research Center, the percentage of Republicans who said parents should be able to forego the MMR (measles, mumps, and rubella) vaccine for their public school children, even if it may create a health risk for others, more than doubled from 20% in 2019 to 42% in 2023. White evangelical Protestants showed a nearly identical pattern with the percentage supporting parents’ decision not to vaccinate their children despite the health risk to others doubling from 20% to 40%.

This is obviously concerning. Measles cases in the U.S. spiked in 2019 to levels we hadn’t seen in decades. Studies showed this was tied to growing vaccine hesitancy, much of which was due to (sometimes deliberate) misinformation about the connection between childhood vaccines and autism. So why just after a decades-high measles spike would we see conservatives even more enthusiastic about normalizing reluctance to vaccinate children?

Several reasonable explanations immediately jump out from the study. Pew shows there’s a strong connection between skepticism over the COVID-19 vaccines and childhood MMR vaccines. And America’s siloed media landscape has played a demonstrable role in fomenting skepticism toward even those vaccines that have proven safe and effective for decades like the MMR shot.

But what ties these factors together isn’t primarily scientific ignorance about the effectiveness or safety of such vaccines. Rather it’s a combination of partisan polarization and a growing populist identity that prioritizes parents’ rights over expert recommendations, state mandates, or the safety of others. That’s actually a bigger problem than ignorance.

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There’s an interesting paradox in Pew’s study. Despite the large change in Republican support for parents to avoid vaccinating their children with the MMR vaccine, Republicans did not change much in their beliefs about the vaccines themselves. Between 2019 and 2023, the percentage of Republicans who thought the benefits of the MMR vaccines outweigh the risks only declined 3% from 89% to 86%. And the percentage who felt there was a high risk of side effects hardly changed at all.

There’s a nearly identical pattern for White evangelicals. In fact, the percentage of White evangelicals who say the benefits of childhood MMR vaccines outweigh the risks didn’t change at all from 2019 to 2023, staying right at 87%. And those who thought the vaccines posed a medium or high risk of side effects only increased 5% from 32 to 37%.

It’s not primarily about fear of vaccines per se. If that were the case, Black Protestants would be the most supportive of leaving their children unvaccinated. Likely owing to a long history of negative interactions with healthcare providers and lower education on the subject of vaccines, Pew shows Black Protestants are even more skeptical about MMR vaccines than White evangelicals. But they’re about half as likely (21% to 40%) to agree parents should be able to decide not to vaccinate their children.

Rather than beginning with ignorance, the conservative shift seems to reflect an amplification of problems that precede the past four years: Political polarization and populist distrust in experts. This then drives political and religious conservatives to sources and relationships where vaccine hesitancy is more normalized.

Political and religious conservatives were already more likely to be antivaxxers before COVID-19. In fact, former president Donald Trump likely contributed to their skepticism. Before he became president in 2016, Trump frequently tweeted claims that childhood vaccines cause autism. And a recent experimental study shows when Trump voters were shown his numerous tweets, they became even more skeptical about vaccines than they were before.

How did COVID-19 response amplify this problem? Despite the COVID-19 vaccine owing its rapid development to Trump’s administration, support for COVID vaccine mandates quickly became associated with the political left.

Research shows “motivated reasoning,” often driven by a natural bias toward promoting our group above others, consistently overrides any evaluation of facts. Following one of the most contentious elections in American history, ideological and partisan identities both direct Americans’ consumption of vaccine news and provide the lenses through which they read it.

Consequently, no matter how many meta-analyses show that COVID-19 vaccines are safe and effective, the narrative on the right must be that they pose grave health risks and are ineffective. Indeed, this is exactly what Pew found among both Republicans and White evangelicals.

But there is also the growing populist skepticism toward experts and normalization of individualized vaccine choices. Pew found only 37% of Republicans said they had “A lot” of trust in their own doctors to give them accurate information about MMR vaccines, compared to 55% of Democrats. Again, this doesn’t point to a skepticism about vaccines per se, but about skepticism toward experts. And Pew shows in other reports that this partisan gap in trust toward experts is widening.

Lastly, childhood vaccine hesitancy is becoming normalized. Here’s an indicator. Pew asked Americans whether they would feel uncomfortable or comfortable letting their child spend time with a child who had not received the MMR vaccine. Over two-thirds (67%) of Republicans said they would be comfortable compared to only 42% for Democrats. Part of this may be the polarization issue, but it also likely reflects that Republicans simply know more parents who have chosen to keep their children unvaccinated.

Scientists can bridge information gaps. We can publicize findings. Ignorance is not an insurmountable barrier. But an identity built around distrust in experts, and particularly any experts who are suspected of serving the narrative of leftists and elites, is more problematic. It’s even more so if those communities are increasingly isolated.

There may be little chance of depoliticizing COVID-19 vaccines at this point, and that will have consequences. But we should all be invested in depoliticizing narratives around childhood vaccines that have proven safe and effective for decades. The future of all our children is at stake.