The Chicago teachers union in a recent letter advised members to keep secret whether they’ve received a COVID-19 vaccine. “Last week, Chicago Public Schools announced a new Board Rule allowing it to instruct all employees to provide CPS their vaccination status by tomorrow. Remember, CPS made this request without notifying or negotiating with the Union,” the Chicago Teachers Union (CTU) said in the letter. “We asked all members last week to wait for our legal review of the matter before completing the CPS form. We continue to recommend that members wait to respond to the vaccination survey form, despite CPS announcing a deadline of tomorrow.” The letter was obtained and published by CBS Chicago. A CTU spokesperson didn’t return requests for comment. The Chicago Board of Education on Feb. 24 unanimously approved requiring all Chicago Public School (CPS) employees to tell the district whether or not they’ve gotten a COVID-19 …