Using simulations, researchers at Vanderbilt University have uncovered new insights into vaccine hesitancy have shown that external factors such as vaccine mandates and availability have varied and sometimes contradictory influences on people’s willingness to get vaccinated. The research was published in the journal PLOS Global Public Health, and the simulations are available to be reviewed on GitHub.
Building on a new mathematical model that represents vaccine hesitancy as a belief that can influence whether parents vaccinate their children, Nicole Creanza, assistant professor of biological sciences, and postdoctoral scholar Kerri-Ann Anderson extended their work to include the effect of external factors that affect vaccine availability, such as vaccine mandates and vaccine inaccessibility.
“Instead of modelling vaccine mandates and inaccessibility as a physical driver or barrier to vaccination, respectively, we considered their effects from a cultural perspective,” Anderson said. “We model the effects of these external factors by considering how beliefs interact with them to shape vaccination behaviours. Our data shows that a vaccine mandate has a lesser consequence on a person’s motivation to vaccinate if they already had very positive feelings about vaccines.”
The findings also demonstrate that when large groups trust vaccines, they usually get vaccinated. But if there aren’t enough vaccines, even those who trust them might not get them. In addition, when vaccine mandates are in place, it can seem like everyone is getting vaccinated. But more people than researchers expected might still be unsure about vaccines and not get them.
“We hope that our research emphasises how important it is to not generalise populations based on a single characteristic or assume populations behave similarly or beliefs have similar influences across varying circumstances,” Anderson said.
“This research provides a better understanding of how public health policies could interact with cultural dynamics to bring about unexpected outcomes,” Creanza said. The research was funded by the John Templeton Foundation, and both researchers are members of the Evolutionary Studies Initiative.
Next, Creanza and Anderson aim to make a model to explore how people respond when a new vaccine (eg for COVID), is introduced. When a novel vaccine is initially introduced, people tend to exhibit more unpredictable behaviour, even those who have confidence in established vaccines, Creanza said.
Source: Vanderbilt University
