The COVID-19 pandemic directly threatened our health and safety, while contradictory scientific and media reports generated uncertainty. Social information processing theory suggests that employees may have relied on their coworkers, via coworker support, to make sense of the confusion. Because previous research shows that coworker support can counterintuitively increase strain, we investigated the effects of coworker support on strain during the pandemic. Specifically, we collected data from a heterogeneous US sample of 314 working parents in May 2020 to illustrate the path from personal traits (i.e., optimism, generalized self-efficacy, and internal locus of control) to COVID-19 anxiety to workplace outcomes (i.e., self-rated performance, emotional exhaustion, and work-family conflict) in a multiphasic study design. Employees with low levels of these traits reported more COVID-19 anxiety, and in turn, more decrement to their workplace outcomes. This mediation is moderated by coworker social support, such that the indirect effect is exacerbated by coworker social support. This is consistent with social information processing theory, which states that coworker social support can unintentionally corroborate and amplify employee stress perceptions. We therefore recommend that, when faced with significant adversity, organizations provide communication training oriented toward increasing positive coworker interactions and guiding social information.