Coronavirus Survival Highlights Need for Careful Removal and Handling of PPE

Researchers Lisa Casanova, PhD, William A. Rutala, PhD, David J. Weber, MD, and Mark D. Sobsey, PhD, from the Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, and the Department of Medicine at the University of North CarolinaChapel Hill, report in Infection Control & Hospital Epidemiology that in the absence of rigorous decontamination, viruses may survive on objects of personal protective equipment (PPE) for hours, posing a continued risk of transfer to the wearer during handling over multiple uses.

The researchers add, "The potential long-term survival of viruses on contaminated PPE is an important factor when formulating recommendations for removal and handling of used PPE and reuse of PPE in the pandemic setting. It also highlights the continued importance of reinforcing good hand hygiene after PPE removal for preventing the spread of infection."

Casanova, et al. (2010) explain that other studies have shown that viruses can survive on PPE materials, "suggesting that items of PPE may pose a risk of disease transmission if they become contaminated with infectious viruses and if virus transfer to hands occurs during handling. Healthcare workers and patients face emerging risks posed by coronaviruses and human-derived and non-human derived influenza viruses (eg, novel H1N1 and avian H5N1 viruses) in healthcare settings. Data on the survival of enveloped viruses on PPE is important for assessing risks posed by handling of contaminated PPE and for making decisions regarding extended use or reuse of PPE in outbreak settings."

In their study, the researchers using a surrogate for SARS coronavirus -- transmissible gastroenteritis virus (TGEV) -- to examine the survival and inactivation of coronaviruses on PPE. Test materials consisted of contact isolation gowns, latex gloves, respirators, hospital scrubs, and nitrile gloves.

The researchers report that coronavirus survival on PPE items varies by material, but infectious virus was detectable on all materials for at least four hours. They report further, "Only a small amount of infectious virus (0.8 log10) was lost on an N95 respirator within the first two hours, and virus was detectable for up to 24 hours (loss of 3 log10). On gowns, TGEV was detectable for up to 24 hours, with a 1-log10 decrease over two hours and a 3-log10 decrease by 24 hours. Virus was still detectable at four hours on scrub fabric. Survival on latex and nitrile gloves was comparable, with a 1.3-log10 decrease by 2 hours and a 2.5-log10 decrease by four hours."

Reference: Casanova L, Rutala WA, Weber DJ and Sobsey MD. Coronavirus Survival on Healthcare Personal Protective Equipment. Infect Control Hosp Epidemiol 2010;31:560-561.