When the news broke that a second health worker in Texas had tested positive for Ebola, stocks related to the deadly virus got a boost. Shares remain up for companies that make hazardous material (hazmat) suits and face masks, and overall consumer sales for protective gear are on the rise. But if healthcare workers donning sanctioned personal protective equipment, or PPEs, are still becoming infected with the Ebola, is the gear doing its job?
Ebola spreads when the body fluids of an infected person meet the broken skin or mucous membranes of an uninfected person. (Contact with contaminated objects and infected animals are also means of transmission.) Public health management of Ebola includes quarantine, avoidance, engineering controls, smart work practices, administrative controls, and proper use, donning and doffing of protective equipment. But what about the equipment itself?
NPR asked Armand Sprecher, the medical adviser to Doctors Without Borders for hemorrhagic fevers, if the suits have any weaknesses that might put a health worker at risk, and he replied that the group's DuPont suits are very fluid-impervious. But to work, they must be used in partnership with correct behaviors and procedures.
“Where we see healthcare worker infections when the PPE is in place, [the worker] did something to override the PPE,” he said. “They didn't wear it appropriately or contaminated their hands in the process of getting [the suit] off.”
Authorities concur that protocol is where problems happen. But what makes the suits so protective in the first place? To figure that out, we poured over DuPont’s Protective Clothing for Ebola Virus Disease Technical Bulletin to see how a jumpsuit that looks like it's made out of paper can protect against a deadly virus.
The DuPont products that meet the requirements of North America standards for blood-borne pathogens are made of DuPont fabrics Tychem QC and Tychem SL with taped seams. (Since these acronyms come up in the conversation, ASTM F1670 is a synthetic blood penetration test and ASTM F1671 is a viral penetration test.)
Both of these materials begin with Tyvek, an “engineered sheet structure” registered by DuPont in 1965. It is a family of tough, nonwoven materials — "spunbonded olefin sheet products," to be precise — that are stronger than paper and combine properties of paper, film and cloth. According to the Tyvek product page, spunbonded olefin is a “strong, lightweight, flexible, smooth, low-linting, opaque and resistant to water, chemicals, abrasion and aging.” You may be familiar with the extra-strong envelopes that are made from the same material.
The Tychem QC fabric starts with Tyvek and then has a polyethylene coating for added chemical protection; Tychem SL is made of Tyvek with Dow barrier film, which is laminated to the fabric to make it more resistant.
The fabrics and seams are tested using recognized procedures to determine the level of barrier against sample materials, according to DuPont. They are not tested against specific viruses, such as Ebola but pass the ASTM tests for “Penetration by Synthetic Blood” and “Penetration by Blood-Borne Pathogens Using Phi-X174 Bacteriophage Penetration as a Test System.”
So getting back to the question of whether or not the equipment works as it should, Sprecher says don't blame the suits. As he told NPR, “things can just go wrong sometimes."
Related on MNN: