positive cases of covid using those baseline tests which means that our schools and classrooms will be significantly safer come tuesday. >> reporter: and that's 50,000 cases out of more than half a million. students, more than 70,000 employees. in addition, they anticipate there could be a lot of staff, you know, not able to come into the buildings because of positive cases so they have four thousand certified professionals ready to come in and fill those rolls in case people are in quarantine. this system of protections, including universal masking, 100% employee vaccination and now about 90% of their students 12 and older vaccinated, has really helped this district keep every campus open throughout this academic year, they haven't had a single school go virtual so they're confident in this system. now, as you mentioned, the surge is very serious right now. children's hospital l.a. did tell me they're seeing more than