An unvaccinated California teacher passed along the Delta variant of COVID-19 to a group of their elementary school students, as well as others, according to a report from the CDC. … On May 23, positive cases of COVID-19 were then reported among the teacher's class of 24, as well as through other staff members, parents, and siblings in close contact with those affected. Each of the infected students at the educational institution were too young to have been vaccinated, per the CDC.