Journal Article

Effectiveness of Face Mask or Respirator Use in Indoor Public Settings for Prevention of SARS-CoV-2 Infection — California, February–December 2021

Dong, Zheng N., Cornejo, Adrian F., Felipe, Diana, Javadi, Mahsa H., DeGuzman, Jennifer L., Dabbagh, Najla, Saretha, Shrey, Ho, Timothy, Lewnard, Joseph A., Watt, James P., Lam, Amanda, Wan, Christine, Bermejo, Miriam I., Spinosa, Michelle M., Park, Hyemin, Miller, Monique, Spencer, Maya, Ni, Jessica, Corredor, Savannah, Dyke, Ashly, Walas, Nikolina, Samani, Helia, Cheunkarndee, Julia, Li, Sophia S., Jain, Seema, Kaur, Amandeep, Openshaw, John, Fang, Anna T., Fukui, Nozomi, Myers, Jennifer F., Xavier, Erin, Poindexter, Diana J., Frost, Paulina M., Barbaduomo, Camilla M., Andrejko, Kristin L., Pry, Jake M., Tran, Vivian H., Abdulrahim, Yasmine

2022

Overview

The use of face masks or respirators (N95/KN95) is recommended to reduce transmission of SARS-CoV-2, the virus that causes COVID-19 (1). Well-fitting face masks and respirators effectively filter virus-sized particles in laboratory conditions (2,3), though few studies have assessed their real-world effectiveness in preventing acquisition of SARS-CoV-2 infection (4). A test-negative design case-control study enrolled randomly selected California residents who had received a test result for SARS-CoV-2 during February 18-December 1, 2021. Face mask or respirator use was assessed among 652 case-participants (residents who had received positive test results for SARS-CoV-2) and 1,176 matched control-participants (residents who had received negative test results for SARS-CoV-2) who self-reported being in indoor public settings during the 2 weeks preceding testing and who reported no known contact with anyone with confirmed or suspected SARS-CoV-2 infection during this time. Always using a face mask or respirator in indoor public settings was associated with lower adjusted odds of a positive test result compared with never wearing a face mask or respirator in these settings (adjusted odds ratio [aOR] = 0.44; 95% CI = 0.24-0.82). Among 534 participants who specified the type of face covering they typically used, wearing N95/KN95 respirators (aOR = 0.17; 95% CI = 0.05-0.64) or surgical masks (aOR = 0.34; 95% CI = 0.13-0.90) was associated with significantly lower adjusted odds of a positive test result compared with not wearing any face mask or respirator. These findings reinforce that in addition to being up to date with recommended COVID-19 vaccinations, consistently wearing a face mask or respirator in indoor public settings reduces the risk of acquiring SARS-CoV-2 infection. Using a respirator offers the highest level of personal protection against acquiring infection, although it is most important to wear a mask or respirator that is comfortable and can be used consistently.

• Publisher: U.S. Government Printing Office,U.S. Center for Disease Control,Centers for Disease Control and Prevention
• Subject: Adolescent / Adult / Aged / California - epidemiology / Case-Control Studies / Child / Child, Preschool / Communicable Disease Control - methods / Coronaviruses / COVID-19 / COVID-19 - diagnosis / COVID-19 - prevention & control / COVID-19 Testing / COVID-19 vaccines / Disease transmission / Effectiveness / Face / Female / Full Report / Function words / Health aspects / Humans / Immunization / Infant / Infection / Infections / Laboratories / Male / Masks / Middle Aged / N95 Respirators / Protection / Protective equipment / Public health / Respirators / SARS-CoV-2 / Self report / Severe acute respiratory syndrome / Severe acute respiratory syndrome coronavirus 2 / Viral diseases / Viruses / Young Adult