This is a preprint with a ton of authors (I didn’t even bother trying to count them!) of a collaborative international study with the goal of examining “whether national identification could explain adherence to the collective behavior change needed to fight COVID-19.” The team analyzed data using multi-level models. Predictor variables used in the study included “national identification,” “political ideology,” and “national narcissim;” outcome variables were “physical distancing,” “physical hygiene,” and “policy support.” The study’s results “revealed that respondents who identified more strongly with their nation consistently reported engagement in public health behaviors and greater support for public health policies." They also found a "small effect of political orientation, indicating that left-wing respondents were more likely to report public health behaviors and support for public health measures than right-wing respondents.”
The lead author, Jay Van Bavel, is on Twitter and posted a great thread explaining the study here.