text: Obesity and immune status in children Childhood obesity with persistent chronic inflammation is a worldwide epidemic Obesity causes dysregulation throughout the immune system affecting the balance and levels of cytokines adipokines and innate and adaptive immune cells The present review focuses on the impact of obesity on immune function in children altering the baseline activation state of immune cells and affecting the ability of the host to combat pathogens and malignancy and respond appropriately to vaccination Obesity causes dysregulation of the immune system Single cell RNA sequencing of adipose tissue and resident immune cells is quantifying the impact of obesity on the frequency of immune cell subsets and their states The system wide alterations in immune function in obesity are most evident upon perturbation including the response to infection e g increased risk of severe COVID 19 in the ongoing pandemic vaccination and malignancy However mechanistic research in pediatric obesity is limited and this impacts our ability to care for these children We must better understand baseline and perturbed immune health in obese children to determine how to account for altered frequency and function of humoral and cellular immune components in acute infection during vaccine design and when considering therapeutic options for this complex medically vulnerable group 