The Informal Safety Net: Social Network Activation among Hispanic Immigrants during COVID-19

During times of crisis, individuals may activate members of their social networks to fulfill critical support functions. However, factors that may facilitate or inhibit successful network activation are not fully understood, particularly for structurally marginalized populations. This study examines predictors of network activation among recent and established Hispanic immigrants during the COVID-19 pandemic. Specifically, using unique, longitudinal data from the VidaSana study and its supplemental survey, the COVID-19 Rapid Response study (N = 400), we ask: How are COVID-related stressors associated with goal-oriented network activation (e.g., health-focused activation) among Hispanic immigrants? How might structural and compositional characteristics of social networks facilitate or inhibit successful network activation during COVID-19? Results align with theories of network activation (i.e., functional specificity) that imply that individuals engage in selective and deliberate activation of networks. That is, we observe a congruency between COVID-related stressors and social network characteristics, and distinct types of network activation. Moreover, we find that respondents experiencing pandemic-induced economic difficulties engage in activation for financial assistance only if they are embedded in a higher-educated network. We discuss the implications of these findings and provide recommendations for future research. © American Sociological Association 2023.

Unraveling the molecular basis of host cell receptor usage in SARS-CoV-2 and other human pathogenic ß-CoVs.

The recent emergence of the novel SARS-CoV-2 in China and its rapid spread in the human population has led to a public health crisis worldwide. Like in SARS-CoV, horseshoe bats currently represent the most likely candidate animal source for SARS-CoV-2. Yet, the specific mechanisms of cross-species transmission and adaptation to the human host remain unknown. Here we show that the unsupervised analysis of conservation patterns across the ß-CoV spike protein family, using sequence information alone, can provide valuable insights on the molecular basis of the specificity of ß-CoVs to different host cell receptors. More precisely, our results indicate that host cell receptor usage is encoded in the amino acid sequences of different CoV spike proteins in the form of a set of specificity determining positions (SDPs). Furthermore, by integrating structural data, in silico mutagenesis and coevolution analysis we could elucidate the role of SDPs in mediating ACE2 binding across the Sarbecovirus lineage, either by engaging the receptor through direct intermolecular interactions or by affecting the local environment of the receptor binding motif. Finally, by the analysis of coevolving mutations across a paired MSA we were able to identify key intermolecular contacts occurring at the spike-ACE2 interface. These results show that effective mining of the evolutionary records held in the sequence of the spike protein family can help tracing the molecular mechanisms behind the evolution and host-receptor adaptation of circulating and future novel ß-CoVs.