The Association between Vaccination Status Identification and Societal Polarization

"The findings indicate that the strength of identifying with one's vaccination status is associated with several measures of polarization of the current debate on COVID-19 vaccination."

Public discord between those vaccinated and those unvaccinated for COVID-19 has intensified globally. Theories of intergroup relations propose that identifying with one's social group plays a key role in the perceptions and behaviours that fuel intergroup conflict. Namely, people tend to view their own social groups (ingroups) as distinctive and superior to other groups (outgroups) and engage in behaviours that confirm this belief. This study tests whether identification with one's vaccination status is associated with societal polarisation.

The study draws on panel data from samples of vaccinated (n = 3,267) and unvaccinated (n = 2,038) respondents in Germany and Austria that were collected in December 2021 and February, March, and July 2022. In both countries, data were collected during heated public debates about the value of COVID-19 vaccination and different vaccination policies, such as vaccination mandates.

To investigate the correlates and consequences of "vaccination status identification" (VSI), the researchers adapted five items from established group identification scales (for example, "I am proud [not] to be vaccinated against COVID-19"). VSI proved sufficiently distinct from vaccination intention and vaccine-related feelings and beliefs: Validation results indicate that: (i) VSI is indeed well described as a group identity among the vaccinated and the unvaccinated in the context of the COVID-19 pandemic; and (ii) VSI is empirically related but conceptually different from other vaccination-related perceptions and behavioural intentions.

The findings confirm that VSI explains substantial variance in a range of polarising attitudes and behaviours. For example, when rating the distinctiveness of the groups of vaccinated and unvaccinated people, higher levels of VSI were positively correlated with greater perceived intergroup differences for both vaccinated and unvaccinated individuals. In contrast, both groups perceived members of their respective ingroup to be more similar to each other the higher VSI was. Outgroup members were also perceived to be more similar to each other as the respondent's VSI increased, although this result was more noticeable among unvaccinated than among vaccinated respondents.

In December 2021, mean VSI was medium to high and varied considerably between individuals, with somewhat higher overall levels among the vaccinated than among the unvaccinated. Participants who decided to get vaccinated between December 2021 and July 2022 (n = 144) showed lower levels of VSI in December compared to unvaccinated participants who did not get vaccinated and thus did not change their group membership. Unvaccinated individuals' VSI in December 2021 was thus predictive of their subsequent likelihood of vaccine uptake: The lower their previous VSI, the higher the likelihood of getting vaccinated.

Among the vaccinated, individuals were found to identify more strongly with their vaccination status when they were older, trusted the government more, when they reported that people important to them were vaccinated (descriptive norm to be vaccinated), and when they assumed that people important to them thought that one should be vaccinated (injunctive norm to be vaccinated). VSI was also stronger among those who reported searching more frequently for COVID-19-related information (e.g., online). Left-wing voters identified less with being vaccinated than centrists, and the same was true for right-wing voters and non-voters.

Higher levels of VSI were associated with perceiving the public discourse as more positive among the vaccinated but as more negative among the unvaccinated. The results were similar for general perceptions of being discriminated against, measured in December 2021. Among vaccinated individuals, average perceived discrimination was low; among the unvaccinated, it was higher and increased with VSI. The same pattern was found for severe forms of discrimination (e.g., social exclusion) measured in February 2022s. Ostracism was not related to VSI among the vaccinated but was found to be positively related among the unvaccinated. (This finding coheres with previous research indicating that vaccination is perceived as a social contract among vaccinated people, where violating this social contract by not getting vaccinated is more harshly punished by vaccinated people.) In a series of dictator games, it was found that the more vaccinated people identified with being vaccinated, the more they discriminated against unvaccinated players, which suggests that reports of discrimination are factual and not just a matter of perception.

VSI was also related to higher psychological reactance toward mandatory vaccination policies among the unvaccinated. Furthermore, the researchers investigated whether those individuals who indicated they would participate in a demonstration (activism) against mandatory vaccinations or sign a petition in December 2021 actually reported having done so in February 2022 and whether this link was influenced by VSI. Indeed, intention was found to predict behaviour: A regression analysis  revealed that activist behaviour was more likely when intention was high. The effect was moderated by VSI, with higher identification increasing the effect of intention on behaviour.

In short, this study found that VSI accounts for much of the variance between vaccinated and unvaccinated individuals' perceptions of public discourse, factual and perceived discrimination, and the quality and strength of their responses to mandatory vaccination policies. "As VSI also related to patterns of traditional and social media use, political preferences and differences in perceived social norms, it seems plausible that the unvaccinated and vaccinated constitute coherent and distinct social clusters ('bubbles')..., which can be seen as a further catalyst of group conflict."

Practical implications of the study include:

• Besides being associated with polarisation and potential conflict, VSI may also impede the success of vaccination campaigns. Appeals to identify with vaccination or a vaccinated society may backfire; talking about vaccination as a simple health intervention may be more successful.
• Previous research indicates that maintaining procedural fairness - for example, by government officials treating vaccinated and unvaccinated individuals in a fair, respectful, and neutral way - could help de-escalate the situation and provide a new basis for discussing and implementing effective and acceptable vaccination policies in the future.
• The rationale behind vaccination mandates could be revisited in public discussions. Somewhat counterintuitively, mandating vaccinations could help reduce the identification of those who have been vaccinated for a long time. Once almost all people have been vaccinated due to mandatory regulations, being vaccinated will consequently become a less important part of one's self-concept. "In this way, effective (enforced) mandates could not only help to end the pandemic but also mitigate conflicts between vaccinated and unvaccinated groups, thereby fostering social cohesion."

In conclusion: "VSI may be important to understanding when a private and personal vaccination decision can become an important aspect of group membership that defines people's self-concept."