Component A: Project Summary Texas Children’s Hospital (TCH) aims to continue inpatient and emergency department surveillance as part of the larger national New Vaccine Surveillance Network (NVSN) to assess the burden of pediatric respiratory and gastrointestinal illnesses and acute flaccid myelitis in hospitalized children and children seeking care in the emergency department. Specifically, we will operate year-round surveillance to assess the burden of multiple viral and bacterial respiratory pathogens, including but not limited to SARS-CoV-2, influenza, respiratory syncytial virus, human metapneumovirus, parainfluenza virus, coronavirus, rhinovirus, and emerging respiratory pathogens, such as enterovirus D68. A concurrent group of healthy, asymptomatic children presenting to Texas Children’s Pediatric practices for well child care will be enrolled as a control group. Nose and/or throat swabs will be collected from symptomatic and healthy control children and tested for a wide array of respiratory pathogens using molecular methods in the laboratory of Dr. Pedro Piedra, a national expert in pediatric respiratory disease. In addition, we will assess the burden of gastrointestinal pathogens such as rotavirus and norovirus. Stool specimens from symptomatic patients and healthy control children will undergo molecular testing in the labs of Dr. Robert Atmar and Dr. Sasirekha Ramani at Baylor College of Medicine. Complete vaccination histories will be obtained for all children based on our well-established process for gathering vaccination histories. We will calculate baseline and population-based rates of respiratory and enteric pathogens among hospitalized and ED patients. Using a test negative study design, we will calculate vaccine effectiveness for vaccine-preventable diseases such as influenza, rotavirus and SARS-CoV-2, comparing symptomatic patients who test positive for a pathogen of interest to symptomatic patients and asymptomatic, healthy controls who test negative for the specific pathogen. Importantly, TCH is an exemplary surveillance site due the large number of admissions each year (>36,000), racial and ethnic diversity of the Houston area, and the similarity of the TCH population to that of the community. Given the large number of admissions per year and depth of local neurologic expertise, TCH represents the ideal site for conducting year- round surveillance for children with acute flaccid myelitis (AFM) and comparing rates of AFM with rates of circulating respiratory and gastrointestinal pathogens.