A Comment on 'Modeling COVID-19 Scenarios for the United States'

Abstract

A recent paper published in the journal Nature-Medicine from the Institute for Health Metrics Evaluation (IHME) claimed that as of September 21, 2020 only 49% of Americans have adopted mask usage in public in response to the ongoing COVID-19 pandemic. By implication, the IHME authors suggest there are still substantial gains to be had by moving toward universal mask adoption, including saving as many as 130,000 lives. As this comment documents, the IHME authors appear to have relied upon outdated survey responses from the late spring and early summer to reach their 49% mask use estimate for September. More recent surveys indicate the United States has moved rapidly toward universal mask adoption, with actual public use rates hovering between 75-80% as of late September. This figure suggests we are much closer to the minimum 85% mask adoption target of the IHME model than their paper indicated. As a result, the gains from additional mask adoption between the present and February 2020 are likely significantly smaller than the IHME model projects.