CDC calls for universal face mask use in US, says it's one of the 'most powerful weapons' to fight coronavirus
There is increasing evidence that cloth face coverings help prevent people who have Covid-19 from spreading the virus to others, says the agency
As cases continue to rise in several parts of the US, the US Centers for Disease Control and Prevention (CDC) is finally recommending universal face masking to prevent the spread of Covid-19. In an editorial, the CDC reviews 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, says the agency. The authors explain that covering mouths and noses with filtering materials serves two purposes: personal protection against inhalation of harmful pathogens and particulates, and source control to prevent exposing others to infectious microbes that may be expelled during respiration.
"We are not defenseless against Covid-19. 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," says CDC Director Dr Robert R Redfield, a co-author of the editorial, published in JAMA.
While US President Donald Trump has been mostly dismissive of face coverings, the CDC experts now emphasize that public messaging needs to be clear and consistent. The agency says public health officials and leaders need to ensure that Americans understand clearly when and how to wear cloth face coverings properly and continue building the evidence base for their effectiveness. "The public needs consistent, clear, and appealing messaging that normalizes community masking. At this critical juncture when Covid-19 is resurging, broad adoption of cloth face coverings is a civic duty, a small sacrifice reliant on a highly effective low-tech solution that can help turn the tide favorably in national and global efforts against Covid-19," write authors.
Early in the pandemic, the CDC recommended that anyone symptomatic for suspected Covid-19 should wear a face-covering during transport to medical care and before isolation to reduce the spread of respiratory droplets. After emerging data documented transmission of Covid-19 from persons without symptoms, the recommendation was expanded to the general community, with an emphasis on cloth face coverings that could be made more widely available in the community than surgical masks and to preserve personal protective equipment such as N95 respirators to the highest-risk exposures in health care settings. "Now, there is ample evidence that persons without symptoms spread infection and maybe the critical driver needed to maintain epidemic momentum," write authors.
"While community use of face coverings has increased substantially, particularly in jurisdictions with mandatory orders, resistance continues. Some have raised concerns that homemade face coverings made from household fabrics may be inferior compared with commercially manufactured products. Cloth face coverings can substantially limit forward dispersion of exhaled respirations that contain potentially infectious respiratory particles," says the CDC team. The experts write that while cloth face coverings are generally well tolerated for short periods, with prolonged use they can be irritating or difficult for some people to breathe through, especially in hot or humid environments. "Innovation is needed to extend their physical comfort and ease of use," they add.
The current review includes two case studies. One shows that adherence to universal masking policies reduced Covid-19 transmission within a Boston hospital system, and another shows that wearing a mask prevented the spread of infection from two hairstylists to their customers in Missouri.
In the Missouri case, analysis shows that a policy mandating the use of face coverings was likely a contributing factor in preventing transmission of Covid-19 during the close-contact interactions between stylists and clients in a salon. The investigation focused on two hairstylists — infected with and having symptoms of Covid-19 — whose salon policy followed a local ordinance requiring cloth face coverings for all employees and clients. 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 coverings 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," say experts.
The CDC editorial also says that acceptance of face mask guidance has increased among Americans. On April 3, the White House coronavirus task force and CDC recommended that people wear cloth face coverings in public to slow the spread of Covid-19. Following the announcement, the proportion of US adults who chose to do so increased, with 3 in 4 reporting they had adopted the recommendation in a survey.
The agency analyzed data from an internet survey of a national sample of 503 adults during April 7-9 and found that about 62% said they would follow the newly-announced recommendations to wear a face mask when outside the home. A repeat survey during May 11-13 showed that the percentage of adults endorsing face masks increased to more than 76%. The increase was driven largely by a significant jump in approval by White, non-Hispanic adults, from 54% to 75%.
Approval among Black, non-Hispanic adults went up from 74% to 82% and remained stable among Hispanic/Latino adults at 76% and 77%. There was also a large increase in face mask approval among respondents in the Midwest, from 44% to 74%. Approval was greatest in the Northeast, going from 77% to 87%. “Public health messages should target audiences not wearing cloth face coverings and reinforce positive attitudes, perceived norms, personal agency, and physical and health benefits of obtaining and wearing cloth face coverings consistently and correctly," recommends CDC.