COVID-19 unmasked: preschool children's negative thoughts and worries during the COVID-19 pandemic in Australia.

: The COVID-19 pandemic and its consequences are stressful for many children and their families. Previous research with school-aged children has shown that negative thoughts and worries can predict mental health symptoms following stressful events. So far preschool children have been neglected in these investigations. : The aim of this study was to explore negative thoughts and worries that preschool aged children are having during the COVID-19 pandemic. : As part of a larger mixed-method study, caregivers of = 399 preschoolers aged between 3 and 5 years ( = 4.41) answered open-ended questions about their COVID-19 related thoughts and worries. Reflexive thematic analysis was used to identify relevant themes from the qualitative data. A theoretical model of child thoughts and worries was developed based on these qualitative findings and the existing empirical and theoretical literature. : Caregivers gave examples that indicated that preschoolers had difficulties understanding causality and overestimated the risk of COVID-19 infection. Caregivers reported that their children expressed worries about getting sick and infecting others as well as about changes in daily life becoming permanent. Caregivers observed their children's preoccupation with COVID-19 and worries in conversations, play and drawings as well as in behavioural changes - increased arousal, cautiousness, avoidance and attachment-seeking behaviour. : Preschool children can and do express negative thoughts and worries and have also experienced threat and increased vulnerability during the COVID-19 pandemic. A theoretical model is proposed that could inform assessments, interventions and future research in the field.