In COVID-19 clinical update #109, Daniel Griffin discusses cardiac complications after infection or vaccination, long COVID in children, fourth vaccine dose in Israel, no need for fourth vaccine dose in EU, dexamethasone dosing, immunomodulation therapy, MIS outcomes in children, US long COVID effort launched, and herd immunity. Subscribe (free): Apple Podcasts, Google Podcasts, RSS, email Become a patron of TWiV! Links for this episode Cardiac complications after infection or vaccination (MMWR) Long COVID in children (Future Med) Fourth vaccine dose in Israel (NEJM) No need for fourth vaccine dose (Eur Med Agency) Dexamethasone dosing (Intensive Care Med) Actemra priority review (Roche) Guidelines on anticoagulation therapy (American Soc Hematol) MIS outcomes in children  in children (JAMA) Biden launches long COVID effort (USA Today) Herd immunity and COVID (J Inf Dis) Contribute to ASTMH fundraiser at PWB Dr. Griffin’s treatment guide (pdf) Letters read on TWiV 886 Timestamps by Jolene. Thanks! Intro music is by Ronald Jenkees Send your questions for Dr. Griffin to [email protected]