A letter from top-level doctors and researchers arguing against the effectiveness of indoor mask mandates, along with pushback from health departments, cities and business groups, possibly played a role in a surprise decision not to re-institute the mandate in Los Angeles County last month.

This newspaper obtained a copy of a February 2022 letter signed by doctors from UCLA's Geffen School of Medicine and USC's Keck School of Medicine sent to the Los Angeles County Board of Supervisors, asking the county to end the mask mandate that was in effect this past winter, claiming the policy did not work.