Even though the COVID-19 pandemic is no longer at its peak, the threat still lingers. Engaging in prospective surveillance studies will enable us to monitor the disease and prepare for any potential resurgence. COVID-19 surveillance studies are essential tools for policymakers to make informed decisions, allocate resources, and develop strategies to control the spread of the virus and protect public health. The objective of this surveillance study is to prospectively assess in-hospital severe morbidity related to COVID-19 infection in children who present to the Pediatric Emergency Department (ED). A prospective multicenter study will be conducted across eight EDs in Israel and five EDs in the United Kingdom. The study population will include children aged 16 years or younger with a severe acute COVID-19 infection. Confirmation of acute COVID-19 infection will be based on polymerase chain reaction nasopharyngeal swab testing. The study will also include patients diagnosed with multisystem inflammatory syndrome in children (MIS-C), as defined by the CDC.