Arizona
Teachers in Phoenix, Arizona, in the Chandler Unified School District, threatened a mass calling in sick in response to a decision by education authorities to continue with face to face teaching. As a result the district was forced to return its students, from preschool up to the 12th grade, to virtual learning starting on January 6th through to January 19th.
A survey by the Chandler Education Association indicated that 65% of 1,200 teachers did not feel happy returning to in-person teaching. They are well aware that virtual learning is not ideal, but feel that it is worth the temporary problems in order to get COVID back under control.
This followed a demonstration by teachers and their supporters outside the district board offices. Teachers in the Gilbert area schools also threatened a sickout if classes resumed. See here for more info.
Chicago
Elsewhere, Chicago teachers staged a similar sickout. Teachers there also also criticised the expectation that they teach simultaneously to in-person and at-home students. More info here.