Researchers are studying COVID-19 at a breakneck pace, with some scientists demonstrating the virus transfers not only between two people, but also between exposed surfaces and individuals. This finding has created a general surface phobia, characterized by a fear of door handles, handrails, and other high-contact objects.

Not all materials offer a lasting home for viruses, however, which could influence professionals when designing spaces for more vulnerable occupants.

In a study by U.S. National Institutes of Health virologist Neeltje van Doremalen and her coauthors, they found that SARS-CoV-2 (the virus responsible for COVID-19) survives for two to three days on surfaces like plastic and stainless steel. The researchers also found that the virus can remain active on cardboard for up to 24 hours, while it dies on copper, in about four hours.

Copper and its alloys such as bronze or brass are inherently antimicrobial, disrupting key cell functions once the metals are exposed to bacteria or viruses. Studies have shown that E. coli survive less than 90 minutes on a copper surface at room temperature. In contrast, the bacteria exhibit no signs of reduced viability after 270 minutes on stainless steel. The same study indicates a similar response in COVID-19. Not only is SARS-CoV-2 rendered inactive within four hours on copper, but SARS-CoV-1—the “most closely related human coronavirus”—also becomes inviable within eight hours.

Although not included in the study, antimicrobial coatings are commonly used to eliminate viruses on material surfaces such as doorknobs, countertops, and wall surfaces. A swiftly growing industry has quietly and rapidly formed around such coatings. While some paint manufacturers have added microbe-killing agents to paint and primer coatings, other manufacturers have created coatings leveraging other chemical capabilities. For example, organosilanes are silicon-based nanocoatings that form a highly-abrasive surface for viruses and bacteria, effectively ripping them apart. Meanwhile, the chemical compound quaternary ammonium, typically used in disinfectants, causes cell leakage and eventual death of microbes.

While these substances hold potential, concerns remain over an increased prevalence of chemicals in the built environment. For example, when the CDC found “no evidence to suggest the products offer any enhanced protection from the spread of bacteria and germs,” Oakland, Calif.–based healthcare provider Kaiser Permanente issued a ban on 15 antimicrobial chemicals used in interior applications. It is unclear whether the mechanical approach will be encouraged as an alternative to chemical antibiotics. —Blaine Brownell

This story was excerpted from ARCHITECT.