before. >> reporter: tensions mounting in chicago. more than 340,000 students missing school for a fourth day. teachers refusing to return to the classroom. >> we're very frustrated that there are no public health leaders standing up and saying we should be moving to remote learning environment especially for a district of this size. >> reporter: in los angeles, students are due back in school in person with widespread testing turning up some 50,000 positive cases in the district. met koro atlanta schools return to in person learning after a week of going remote. new york city schools started the new year in person. so far one single classroom in partial quarantine. >> i think there's no good explanation for having remote schools. >> reporter: a more dire situation for hospitals. nearly one in four nationwide reporting critical staffing shortages. while covid hospitalization numbers near the pandemic all time high.