Persistent media skepticism shapes common vaccine conspiracy beliefs

A research team led by Professor Hitoshi Yamamoto of Rissho University analyzed five years of longitudinal panel survey data collected between 2020 and 2024 and examined how vaccine-related conspiracy beliefs were associated with media skepticism during the COVID-19 pandemic. The study's results appeared in Scientific Reports on August 8, 2026.

Researchers analyzed annual survey data collected from the same participants over five consecutive years to examine how media use, media skepticism, and subjective media literacy were related to later vaccine conspiracy beliefs.

The analyses suggested that vaccine conspiracy beliefs may involve at least two distinct aspects. One reflects distrust of institutions, including beliefs that governments or pharmaceutical companies conceal information. The other involves highly implausible claims, such as the belief that vaccines contain microchips. These two aspects differed in both their prevalence and the factors associated with them.

In particular, conspiracy beliefs rooted in distrust of institutions were more strongly associated with persistent skepticism toward mainstream media and with increasing skepticism over the course of the pandemic.

By contrast, only a relatively small minority of respondents endorsed highly implausible conspiracy beliefs, such as claims that vaccines contain microchips. The researchers note that these extreme claims may nevertheless appear more prominent in online environments, including social media.

The study is also notable because it examined conspiracy beliefs in Japan, where the media environment is generally considered less politically polarized than in many Western countries. The findings suggest that conspiracy-related beliefs can emerge even in informational environments characterized by relatively broad social consensus.

Professor Yamamoto commented:

"When people think about conspiracy beliefs, attention often focuses on highly extreme claims. However, our findings suggest that more common forms of conspiracy-related thinking are associated with persistent distrust of social institutions and the mainstream media. Addressing misinformation may therefore require not only correcting factual inaccuracies, but also understanding how distrust develops and persists within contemporary information environments."