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What are surgical masks and respirators, and why are they important in the fight against COVID-19?

The global pandemic caused by COVID-19 has left many health care providers scrambling for basic personal protective equipment, or PPE. 

Surgical masks and respirators are two forms of PPE that health care providers need to work safely in a pandemic.  

 

What do surgical masks and respirators actually do?

Surgical masks and respirators both act as a barrier that catches hazardous materials before they enter a healthy person’s mouth or nose. 

Surgical masks are loose-fitting pieces of filtering fabric that typically hook over a wearer’s ears and across their face. In a medical setting, masks can be used to protect healthy wearers, but also to prevent a sick wearer’s fluids (in the form of a sneeze or a cough, or speaking in close proximity) from spreading. Though they come in a variety of protection levels, they are most effective in stopping large droplets of fluid, like blood or saliva — but because of their loose fit even when worn correctly, air can still escape along the sides of the mask. 

Medical respirators are cuplike devices that form a tight seal on the wearer’s face. When fitted correctly, inhaled air has to be pulled through the respirator’s filtration material. An N95 designation means that in an optimum setting, the respirator filters out at least 95 percent of  particles as the wearer inhales. Depending on the respirator, the particles it is able to filter out could be thousands of times smaller than a human red blood cell. Because of the intensity of the filtration, N95 respirators can be uncomfortable for the wearer, who may even experience difficulty breathing; the Food and Drug Administration warns that people with respiratory and cardiac issues should not wear them without consulting a doctor. Both forms of PPE are now in short supply all over the world, and were predominantly produced in China prior to the novel coronavirus outbreak. Businesses and production were significantly slowed in China while the country was coping with their outbreak. 

 

How do they work?

The filtration technology in surgical masks and respirators relies on melt-blowing, an expensive process that creates a microscopic plastic mesh. This mesh makes up the inner layer of the PPE filter. The more layers a single PPE unit has, the more protective it is against tiny particles. Surgical masks have two to four thin layers, and respirators have five to six layers that vary in rigidity and density.

But respirators offer more protection than surgical masks because of the way they fit. 

“Surgical masks probably give a small degree of protection, acting as a physical barrier,” said Raina MacIntyre, who leads the Biosecurity Research Program at the University of New South Wales’s Kirby Institute in Australia. In her research, MacIntyre compares how well different PPE protect against illness, in both clinical and home settings. With correct use, respirators fit tightly on the face and are generally the safest option. “Respirators are designed as respiratory protection, and are regulated on filtration capacity,” MacIntyre said in an email. “They fit tightly around the face, and do not allow air leakage. Surgical masks are not regulated on filtration, and allow air leakage around the edges.”

Surgical masks and respirators are ideally used in different situations, said Dr. Maryann D’Alessandro, who directs the National Personal Protective Technology Laboratory at the Centers for Disease Control and Prevention.

“[Surgical masks] protect the patient by limiting the spread of potentially hazardous particles that are expelled by the wearer, and also help provide a physical barrier to protect the wearer from splashes, sprays, or contact with contaminated hands,” D’Alessandro said in an email. When worn properly, respirators are designed to protect the wearer, i.e. a healthcare worker.

Without sufficient training, most people will wear both surgical masks and respirators incorrectly, Dr. D’Alessandro said. Surgical masks have a metal strip that needs to be bent across the nose to ensure they are flush with the face, she said, while respirators require a proper seal and fit before use. 

D’Alessandro’s lab assists in creating the training that is mandatory for every U.S. worker who is required to wear PPE. During these sessions, D’Alessandro said the instructor reviews why a respirator is needed, how to check and test if it fits properly, how to put on and remove the respirator safely, what to do if it is contaminated and how to check each component. 

 

Why are these devices important during a pandemic?

It still remains unclear exactly how the novel coronavirus spreads. Like its relatives SARS and MERS, scientists are confident novel coronavirus, or COVID-19, can spread through direct contact with infected respiratory fluids. However, the latest literature suggests that the virus can survive in tiny, aerosolized droplets (from, say, a sneeze) for several hours, and on nonporous surfaces like stainless steel for several days. In that case, there should be protection against airborne contaminants and ones on physical surfaces. The Centers for Disease Control and Prevention generally recommends that any healthcare provider working with infectious diseases, such as the flu, wear an N95 respirator.

 

Are there safe alternatives?

The CDC’s National Institute for Occupational Safety and Health says that N95s are actually the least protective respirators they have approved for healthcare workers. 

“The N95 provides appropriate protection for healthcare personnel coupled with other interventions, such as hand-washing, cohorting patients and healthcare workers, keeping a six-foot distance, and ventilation,” Dr. D’Alessandro said. “It is a system of protection, not just the respirator, that provides protection.”

Full-face respirators are less commonly used and more protective, but are difficult to clean and maintain, Dr. D’Alessandro said.

As of earlier this month, the United States’ stockpile of respirators and face masks was less than a fifth of what will be needed over the course of the pandemic. A worldwide rush to buy PPE means that healthcare providers are struggling to find enough masks to use — and dispose of — as frequently as usual. To stretch the current supply of available PPE, healthcare providers in the United States are being asked to use their masks and respirators for extended periods of time — in some places full days, and in others, weeks at a time. 

The CDC is now advising that PPE be used beyond their officially-designated shelf lives, and that healthcare providers can reuse the same mask for visiting multiple patients. Masks and respirators designed for industrial use, and not approved by the FDA, can be used to supplement what is available. And as a “last resort,” the CDC says care providers can cover their faces with bandanas and scarves. While the CDC said the benefit of these improvised masks was “unknown,” adding that the wearer would ideally use a plastic face shield as added protection. 

Still, experts say something is better than nothing. Hospitals and healthcare systems across the country are putting out calls for homemade fabric masks, and crafty volunteers are preparing to churn them out by the thousands. Hospitals are saying that these masks will ideally be used in conjunction with other PPE, or for doctors and nurses who are not working with infectious patients. Research suggests that masks made out of a cotton t-shirt are three times less effective in preventing disease than a regular surgical mask, but are still preferable to a bare face.

“In a life-or-death situation where health workers have no other PPE, I could recommend using whatever they can get, including cloth masks,” MacIntyre said. 

Because homemade masks are not sterile, it is vital that a healthcare worker washes their cloth mask daily and invests in equipment to clean the mask for reuse, such as a UV sterilizer. So long as one does not touch their face after removing the mask and cleans it regularly, MacIntyre thinks cloth masks can do more good than harm. 

“Take things into your own hands and protect yourself … If you wear it, it protects,” she advises healthcare providers.

What’s being done to boost the U.S.’ PPE supply?

The pandemic and ensuing equipment shortages have tapped into a nearly century-old debate in the United States: when can the government co-opt private industries’ resources, how, and for how long?

The answer lies in the Defense Production Act, passed under President Harry Truman in 1950. Though federal incentives for manufacturing military goods were used under the War Powers Acts during World War II, the DPA formalized that practice. 

The act gives the president a broad set of powers to issue loans and create contracts with private entities, and block mergers that would “threaten national security.” Agencies like the Federal Emergency Management Agency regularly use the DPA to require equipment manufacturers to prioritize their orders, and it has also been used to help states recover from natural disasters.

President Donald Trump has not actually used DPA powers to address the COVID-19 equipment shortages. The White House may be waiting to see if companies will produce more PPE “partly out of patriotism, and partly out of not having to be [FDA] compliant — or even have had a history of working with the government previously,” said Mackenzie Eaglen, a resident fellow studying defense policy at the conservative American Enterprise Institute.

“I think the White House is hoping companies and their suppliers and vendors will voluntarily step up to help,” Eaglen said.

Conservative ideology and a preference for limited government fuel this approach, Eaglen said. “It’s possible companies and small businesses will volunteer enough to meet demand without needing to nationalize industries or dramatic steps like that, but unlikely is my guess,” she said. 

President Trump has come under fire from Democratic senators and state governments for his hesitation to use the DPA. Though he has claimed on Twitter that the DPA is “in full force,” there is no evidence to suggest any provisions are being used to increase the PPE supply.

PPE manufacturers like 3M, Honeywell and Johnson & Johnson say they have independently made moves to step up their production capacities and prioritize their customers in the health care sector. According to the Trump Administration, 3M has signed a federal contract to produce 30 million more masks every month. Because of the specialized nature of the melt-blowing process and the equipment needed to do it, meeting the skyrocketing demand could take over a year.

The U.S. does not have the luxury of time, with nearly 47,000 known cases and nearly 600 deaths attributed to the virus as of March 25. On Tuesday, the World Health Organization warned that the U.S. could become the next global epicenter for COVID-19. 

 

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