In an editorial published today in the Journal of the American Medical Association (JAMA), CDC reviewed the latest science and affirms that cloth face coverings are a critical tool in the fight against COVID-19 that could reduce the spread of the disease, particularly when used universally within communities. There is increasing evidence that cloth face coverings help prevent people who have COVID-19 from spreading the virus to others. “We are not defenseless against COVID-19,” said CDC Director Dr. Robert R. Redfield. “Cloth face coverings are one of the most powerful weapons we have to slow and stop the spread of the virus – particularly when used universally within a community setting. All Americans have a responsibility to protect themselves, their families, and their communities.” This review included two case studies out today, one from JAMA, showing that adherence to universal masking policies reduced SARS-CoV-2 transmission within a Boston hospital system, and one from CDC’s Morbidity and Mortality Weekly Report (MMWR), showing that wearing a mask prevented the spread of infection from two hair stylists to their customers in Missouri. Additional data in today’s MMWR showed that immediately after the White House Coronavirus Task Force and CDC advised Americans to wear cloth face coverings when leaving home, the proportion of U.S. adults who chose to do so increased, with 3 in 4 reporting they had adopted the recommendation in a national internet survey. The results of the Missouri case study provide further evidence on the benefits of wearing a cloth face covering. The investigation focused on two hair stylists — infected with and having symptoms of COVID-19 — whose salon policy followed a local ordinance requiring cloth face coverings for all employees and patrons. The investigators found that none of the stylists’ 139 clients or secondary contacts became ill, and all 67 clients who volunteered to be tested showed no sign of infection. The finding adds to a growing body of evidence that cloth face coverin provide source control – that is, they help prevent the person wearing the mask from spreading COVID-19 to others. The main protection individuals gain from masking occurs when others in their communities also wear face coverings. COVID-19 prevention in a Missouri hair salon When two stylists at a Missouri hair salon tested positive for the virus that causes COVID-19, researchers from CoxHealth hospitals, Washington University, the University of Kansas, and the Springfield-Greene County Health Department worked together to trace contacts, investigate the cases, and publish their findings in the MMWR. One of the stylists developed respiratory symptoms but continued to see clients for eight days. The other, who apparently became infected from her co-worker, also developed respiratory symptoms and continued to see clients for four days. The salon in which they worked had a policy requiring both stylists and their clients to wear face coverings, consistent with the local government ordinance. Both stylists wore double-layered cloth face coverings or surgical masks when seeing clients. The median appointment time was 15 minutes and ranged from 15 to 45 minutes. More than 98% of clients wore a face covering—47% wore cloth face coverings, 46% wore surgical masks, and about 5% wore N-95 respirators.