risk in terms of not just educational learning but socialization and mental health and all kinds of things that are really, really important. reporter: but according to the data company birbio, more than 3,200 schools are going remote or delaying returns from winter break. l.a. unified school district, the latest to push back its start date by one day and require proof of a negative test. in chicago, the powerful teachers union is threatening a walkout over decisions to bring students back to the classroom. contact tracing and vaccination efforts by her administration have been an abject failure. only 30% of our elementary school students are vaccinated. only 50% of our high school students are vaccinated. reporter: across the country, pediatric hospitalizations are still rare but now at a record high, spurring questions over whether children are being hospitalized for covid or with covid as well as questions about the impact of omicron on children. now, did those children show