The director of the Centers for Disease Control and Prevention, Dr. Robert Redfield, wearing a face mask, is waiting to testify before the House's Energy and Trade Committee on the Trump Administration's response to the COVID-19 pandemic on Capitol Hill in Washington, DC. US June 23, 2020.
Kevin Dietsch | Reuters
The Centers for Disease Control and Prevention said policymakers should consider requesting facial coverings to reduce the spread of the coronavirus after examining two Missouri hair stylists who had Covid-19 but didn't share it with their customers the agency released in a new study Tuesday.
"Given the potential for presymptomatic and asymptomatic transmission, widespread adoption of guidelines that require face coverings in public facilities to reduce the impact and extent of additional waves of COVID-19 should be considered," said the CDC published study.
Some governors, including California Governor Gavin Newsom and Texas Governor Greg Abbott, have made requirements for wearing facewear in public or in certain environments when people are unable to practice social distancing. However, there is no nationwide US mandate like in China and other countries. Not all U.S. states have given mask mandates, and some with major outbreaks, including Florida, have left it to local cities and counties. As CNBC has previously reported, US companies have to enforce face covering requirements themselves.
In an interview with Dr. Howard Bauchner of the Journal of the American Medical Association late Tuesday emphasized the importance of masks. He said the US could control the coronavirus pandemic in a month or two if every American was wearing a mask.
"I think we are very clear now," said Redfield. "Now is the time to wear a mask."
The CDC tracked two infected hairdressers in Springfield, Missouri, who worked while they were contagious, but it appears that they haven't transmitted the virus to any of their 139 customers. One of the stylists developed symptoms on May 12 and continued to work until May 20 when they received a positive Covid 19 test result. During this time, the infected person passed the virus on to another stylist, who also continued working until May 20, although symptoms appeared on May 15, the researchers wrote.
The two stylists worked on 139 customers within eight days, the researchers wrote, but after follow-up visits and interviews, none of them tested positive for Covid-19 or reported breathing difficulties. The researchers concluded that the city-wide regulation, which limited business to 25% capacity and required everyone to wear masks in the salon, helped prevent the virus from spreading.
"A guideline that dictates the use of facewear has probably helped prevent SARS-CoV-2 transmission during the close contact interactions between stylists and clients in Salon A," the researchers wrote. "A more extensive implementation of masking guidelines could reduce the spread of infections in the general population."
When interacting with customers, the two stylists always wore either a "double-layer cotton facial covering" or a surgical mask, the researchers said. They added that customers said they wore either a fabric face mask, surgical mask, or N95 ventilator for all or part of the time they were in business.
The lack of transmission in the hair salon is based on increasing evidence showing that the use of masks and face coverings, especially indoors or in crowded environments, plays an important role in preventing infections. The researchers cited observation data from 194 countries, showing that "countries that did not recommend face masks and respirators" experienced a greater increase in Covid-19 deaths per capita than "countries with masking guidelines".
However, the researchers found some limitations to their study of the Missouri hair salon. Not all customers agreed to a test, and some may have been tested too early in the virus incubation period to receive a positive test, although they may have tested positive later, the researchers said.
A total of 67 customers agreed to be tested and 72 declined, the researchers wrote, but of a total of 139 customers, 104 were interviewed by the Greene County Health Department whether they had developed symptoms. Of the 104 patients reached, 87 reported no symptoms and none of those who reported symptoms received a Covid 19 test.
That is, it is possible that asymptomatic or mildly symptomatic people who may have been infected in the salon may go undetected.
And it is possible that the stylist infected customers before they showed symptoms, but the researchers did not collect data from customers who visited the salon before the first stylist developed symptoms. The researchers also found that the type of hair care where the customer turned away from the stylist could have reduced the risk of infection instead of the masks.
Despite these limitations, the researchers support the widespread use of face masks and masks to reduce Covid-19 transmission. Face coverings have become a political lightning rod in the debate about how best to control the pandemic, but scientists say there is evidence to help contain the outbreak. They say it is particularly important to prevent people who either have no symptoms or whose symptoms have not yet started from spreading them.
"These results support the use of face coverings in public places, especially when social distance is not possible to reduce the spread of SARS-CoV-2," they write.