Infectious Disease



Cicely Enright

Know-how and compassion lead medical teams to treat people suffering with contagious diseases like Ebola. Protective clothing and disinfectants - backed by ASTM standards - help keep them safe.

For people who work in healthcare, it's an everyday thing. Nurses and aides care for patients, doctors perform surgery, and technicians clean and disinfect the area.

But, since last spring, the regular risks have taken on an additional layer of urgency to determine the right precautions in treating Ebola patients.

In the United States, National Nurses United has petitioned President Barack Obama to mandate national standards for protocols and personal protective equipment, including attire that meets F1670 and F1671, for U.S. healthcare workers treating Ebola patients.

The InterAgency Board for Equipment Standardization and Interoperability, which represents public sector emergency preparedness and response groups, references those and other ASTM standards in its recommendations for protecting first responders against Ebola exposure hazards.

California's Cal/OSHA Interim Guidance on Ebola Virus in Inpatient Hospital Settings also references F1670 and F1671 in its protective clothing section, and the U.S. Occupational Safety and Health Administration suggests that coveralls pass one test or the other. And the October 2014 American College of Surgeons surgical protocol for Ebola cases called for the most protective drapes and gowns, again relying on these ASTM tests.

In the nonpharmaceutical infrastructure that helps prevent the spread of infectious diseases, protective clothing and disinfectants - backed by ASTM standards - play a big part.

Protective Clothing

Doctors, nurses and aides must wear personal protective equipment, which includes clothing designed and constructed to protect them from viruses, bacteria and other hazards they may encounter in taking care of people who are ill. As an end user, "I just need to know that I can tell my staff that you need a certain level of protection when you're doing a certain degree of risk," says Janet Lewis, MA, BSN, RN, CNOR. She is the administrative director of perioperative services at Regional West Medical Center, Scottsbluff, Nebraska, and represents the Association of Perioperative Nurses on Committee F23 on Personal Protective Clothing and Equipment. "OSHA says that we as employers not only have to provide protective clothing but to require that it be worn," Lewis adds.

In the 1990s, when OSHA published its requirements1 mandating better safeguards for people who treat patients, there were no standards that identified or quantified blood and fluid repellency. In response, ASTM Committee F23 set to work on standards.

Phillip Johnson, vice president, Johnson Moen and Co. Inc., Rochester, Minnesota, and an F23.40 member since 1992, says that Committee F23.40's response to the OSHA requirements was to adapt another ASTM standard - F903, a liquid penetration test method developed by the F23.30 committee for measuring the resistance of protective clothing materials to penetration by chemicals - for the development of F1670 and F1671. F903 is still referenced in both standards today.

F1670 uses synthetic blood, having the surface tension and viscosity of blood, on samples of a protective material; the samples are exposed to the synthetic blood under hydrostatic pressure in the F903 device for a specified time period, and results are recorded as pass/fail by visual inspection of the sample for blood penetration. F1670 is used to identify those protective clothing materials that warrant further evaluation using F1671. Another test method (F1819) from Subcommittee F23.40 uses a direct mechanical pressure device as an alternative to the F903 device's hydrostatic approach, to evaluate materials used to make protective clothing.

F1671 takes the use of these devices to another level by measuring the resistance of materials used in protective clothing to penetration by blood-borne pathogens using a surrogate microbe under conditions of continuous liquid contact. Protective clothing material pass/fail determinations are based on the detection of viral penetration. This test method has been specifically defined for modeling the viral penetration of Hepatitis (B and C) and human immunodeficiency viruses transmitted in blood, and other potentially infectious body fluids.

"The biggest thing is the sensitivity of the F1671 test," says Todd Hillam, an ASTM and F23 member since 2005. "You can detect down to a very small number - one to two viruses - going through the material." He adds that the virus used in the test, similar in size and shape to blood-borne pathogens, is safe for humans to work with as it only infects other bacteria.

Hillam is protective barriers section leader for Nelson Laboratories Inc. in Salt Lake City, Utah. He notes that the F1671 test is used as described in the PB70 standard from the Association for the Advancement of Medical Instrumentation to claim the highest level of protection for a surgical gown.2 "As a healthcare worker I would want to know I am wearing the highest level of protection available in most instances," Hillam says.

According to the AAMI PB70 standard, Level 1, 2 and 3 gowns and drapes must resist liquid penetration during impact penetration and/or pressure test results. The most protective tier is Level 4; at this level, gowns must pass the ASTM F1671 test, and drapes pass ASTM F1670.

"We use these tests as we look to do AAMI PB70 testing," says Joseph Palomo, engineering manager, global engineering and tech support, at Cardinal Health, Waukegan, Illinois, a provider of healthcare apparel as well as other medical products and services.

Natallie White, quality assurance manager for manufacturer Medline Industries, Mundelein, Illinois, says that the standards are significant: "We believe that the ASTM F1670 and F1671 test standards are critical for helping manufacturers know that they are confidently developing and distributing products that provide specific levels of protection against blood borne pathogens for which end users may be at risk of exposure." She adds that the standards are also important because of their acceptance and use by healthcare agencies.

Hillam notes that the U.S. Food and Drug Administration has a guidance document for surgical gowns that refers to this test, which is used worldwide by manufacturers and distributors.

Antimicrobials

The response to infectious disease includes more than protective garb. Antimicrobials, or disinfectants, also help keep viruses from spreading. "Disinfectants play an important role in disease control," says Steve Zhou, Ph.D., director of virology and molecular biology, MicroBioTest Division, Microbac Laboratories Inc., Sterling, Virginia, and an ASTM member since 2006.

Wherever there's a disinfectant in use - to rid bed rails or counters of viruses, or to wash them from people's hands - ASTM standards demonstrate their usefulness.

These standards come under the purview of Subcommittee E35.15 on Antimicrobial Agents, a part of Committee E35 on Pesticides, Antimicrobials, and Alternative Control Agents, which began work in 1973.

In the non-pharmaceutical approach to stopping the spread of disease, "E1053 is one of the most important methods for verifying the efficacy of a disinfectant or antiseptic product," Zhou says. The standard describes a procedure to assess how well disinfectants work.

Zhou explains the scientific reasons for its value. The method most closely simulates the real-life situation of contamination, when a virus dries on a hard surface. That also makes a virus harder to kill from the start. (It also differentiates the E1053 method from suspension methods such as the European EN methods and ASTM E1052, in which the virus in suspension must be killed.) In this manner, E1053 proves to be more stringent.

For the E1053 method, a liquid that includes the virus - the suspension - dries on a hard surface and the test formulation is then sprayed or applied to the surface. After the formulation dries, further testing checks for infectivity, which shows how well the disinfectant works.

The U.S. Environmental Protection Agency stipulates hard surface-based testing, and it accepts E1053 data from manufacturers submitting disinfectant submissions for review.3 In addition, Zhou notes the standard's use for formulation submissions in Japan and Central and South America; Health Canada accepts the standard, as does the Australian Therapeutic Goods Administration.

E35.15 has also created standards for hygienic handwash because hands can carry and spread viral infections. The group has developed methods to test the virus-eliminating effectiveness of handwashes and handrubs using people's fingerpads (E1838) and hands (E2011). The standards address how well such formulations eliminate viral contaminants, and Health Canada accepts data from these tests.

Challenges and Standards

Information and care protocols for treating infectious diseases are likely to continue to evolve and be needed, and ASTM members continue to respond with relevant standards.

"ASTM International is contributing directly and significantly to developing standards for a better nonpharmaceutical response to Ebola disease," says Zhou.

E55 and Single Use Biopharmaceutical Systems

One time use. It's familiar today in consumer products such as contacts, coffee cups and containers, perhaps more than we might like. But in the field of pharmaceuticals, many more drugs, including vaccines and gene therapies, could be manufactured in single use systems. And that's a good thing.

"The risk of contamination is vastly reduced by using these single use devices," says James Dean Vogel, P.E., founder and director of The BioProcess Institute, North Kingstown, Rhode Island. "Where safety increases, patients benefit."

ASTM Committee E55 on Manufacture of Pharmaceutical Products is tackling standards for single use systems through its Subcommittee E55.04 on General Biopharmaceutical Standards, which is providing a forum for suppliers and users to come together to draft standards for this increasingly common manufacturing equipment.

Systems can be as simple as these common components: bags, tubing, connectors and filters, used together to grow, separate and purify the final product. Whatever a system includes, "the standards will help ensure that equipment meets the needs of the patient for safety and the manufacturing process for consistency," says Robert Steininger, past senior vice president, manufacturing, AcceleronPharma, Cambridge, Massachusetts, current E55.04 chairman and a consultant. "Such standards do not exist at this time."

The key change for the industry is that the Single Use Systems are manufacturered, and usually sterilized, by the suppliers. No matter the exact components, system setup or medicine to be produced, certain questions apply: How can we assure that this equipment does not introduce significant impurities into the drug? How can we be more certain that changes to the plastics don't affect the equipment's properties? How do we know how clean the system is? How clean are these single use systems compared to conventional stainless steel systems, which are cleaned and sterilized by the biopharmaceutical manufacturers? How do we know whether there are particulates and if so, how many and what are they? Until these standards are completed, "we can't reproducibly measure it to know how clean it is," Vogel says. The standards should help provide answers without being too prescriptive.

The proposed standards now underway include practices for standardizing extractable testing, change control, and testing single use system integrity. These standards will be applied in pharmaceutical and biopharmaceutical manufacturing, to control the consistency of the equipment, and the integrity of systems during the production process, including characterizing particulates. Once these are complete, more may come.

"The standards should enhance the ability to provide a safe and efficacious biopharmaceutical product," Vogel says. "The standards will help the industry focus on what it does well: make effective therapies to improve health, not spend time on wondering if single use technology can be used."

REFERENCES

1. U.S. Occupational Safety and Health Administration, CFR 1910.1030, Bloodborne Pathogens.

2. Association for the Advancement of Medical Instrumentation, PB70, Liquid Barrier Performance and Classification of Protective Apparel and Drapes Intended for Use in Health Care Facilities.

3. U.S. Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, OPPTS 810.2200, Disinfectants for Use on Hard Surfaces Efficacy Data Recommendations.

January/February
2015
Industry Sectors: 
Consumer Products
Medical
Safety