A mask policy at a Missouri salon likely helped prevent a pair of stylists who contracted the novel coronavirus from spreading it to any of the nearly 140 clients they came into contact with, according to a new report from the Centers for Disease Control and Prevention (CDC).
The agency on Tuesday touted the findings as evidence for why policies recommending facial coverings can be so important to slow the spread of the coronavirus, which has infected more than 3 million people in the U.S. and accounted for about 136,000 deaths.
Authors of the study noted that some factors prevented them from drawing definitive conclusions. But they said that the findings "support the role of source control in preventing transmission" and asserted that they can inform public health policy.
According to the study, a hair stylist at a salon in Springfield, Mo., on May 12 developed respiratory symptoms for COVID-19, the disease caused by the novel coronavirus. A second stylist developed symptoms for the disease within three days.
The two employees are said to have provided services for 139 clients at the salon in the subsequent days before receiving positive test results. But no COVID-19 symptoms were identified among the clients or their secondary contacts, the study found, noting that the lack of an outbreak may have been linked to a city ordinance and company policy recommending the use of facial coverings.
Both the stylists and 98 percent of the clients who agreed to be interviewed by local health officials said they wore masks throughout their time at the business. The other 2 percent said they wore face coverings part of the time.
After the stylists received positive test results, the salon closed for three days and public health officials conducted contact tracing for all of the 139 clients who received services from them. The Greene County Health Department found that none of the clients exhibited symptoms for the virus as they self-quarantined. Sixty-seven individuals who volunteered to get tested also received negative results.
The report noted that asymptomatic cases could have been missed amid the study. However, it said that the findings pointed to face coverings being a "contributing factor in preventing transmission."
"As stay-at-home orders are lifted, professional and social interactions in the community will present more opportunities for spread of SARS-CoV-2," the authors wrote. "Broader implementation of masking policies could mitigate the spread of infection in the general population."
Federal and state leaders have launched an aggressive push in recent weeks to make face covering more universal as the U.S. experiences a rapid surge in COVID-19 cases. At least 22 states and Washington, D.C., have implemented orders mandating face masks.
However, their use has been the source of tension in some regions, with critics arguing that it represents an infringement on their rights. President TrumpDonald TrumpFormer Sen. Heller to run for Nevada governor Overnight Defense & National Security — Milley becomes lightning rod Joint Chiefs Chairman Milley becomes lightning rod on right MORE has been reluctant to wear a face mask in public. He wore one in view of cameras for the first time last week during a visit to Walter Reed hospital.
In an editorial published in the Journal of the American Medical Association (JAMA), CDC leaders called for universal mask wearing to contain the virus. They pointed to the Missouri report and a JAMA study that found adherence to universal mask-wearing policies reduced transmission within a Boston hospital system as support for the guidance.
“We are not defenseless against COVID-19,” CDC Director Robert Redfield said in a statement. “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.”