Wellness influencers showed higher rates of vaccine opposition on social media compared to other users’ accounts, according to a new University of Michigan study.

New work by U-M School of Information lecturer Elle O’Brien, student Ronith Ganjigunta and UMSI assistant professor Paramveer Dhillon found that wellness influencers were more likely to post messages on Twitter in 2020-2022 (rebranded as X in 2023) expressing anti-vaccination stances during the rollout of the COVID-19 vaccine.

The study, published in the Journal of Medical Internet Research, reveals higher rates of vaccination opposition among Twitter wellness influencers during the COVID-19 pandemic. The paper’s goal, O’Brien said, was to better understand the role of wellness influencers online.

Why do wellness influencers exist, why do they attract such large audiences and what void are they filling?

“One hypothesis is that wellness influencers serve as an alternative to traditional authorities like medical professionals and health scientists when trust in public institutions is low,” O’Brien said. “And indeed, we found support for this idea. Part of the role of being a wellness influencer may be to fill a void left over by diminished trust in traditional experts.”

Notably, about 50% of the wellness influencer accounts identified before the pandemic went on to post anti-vaccine messaging, which was about twice as frequent as a control group of accounts.

“They often shared posts urging followers to protect children from the harms of vaccines, or to oppose authoritarian government overreach,” she said.

O’Brien’s interest in how the public forms attitudes on science began during her previous work as a neuroscientist.

“I’m interested in how people present themselves as scientific, even if they’re not engaging with research in the way that working scientists would,” she said. “And I’m interested in how people decide what counts as valid science when they might not have the specialized knowledge to fully understand it.”