Study: SARS-CoV-2 Can Live for 72 Hours on Plastic, Stainless Steel Surfaces

By Jay Kumar, PSQH 

SARS-CoV-2, the virus that causes COVID-19, can be detected for up to 72 hours on plastic and stainless steel surfaces, according to details of a new study published this week in the New England Journal of Medicine (NEJM).

Researchers from National Institutes of Health (NIH), CDC, UCLA, and Princeton University analyzed the aerosol and surface stability of SARS-CoV-2 and compared it with SARS-CoV-1, the most closely related coronavirus. The study looked at 10 experimental conditions involving the two viruses in five environmental conditions: Aerosols, plastic, stainless steel, copper, and cardboard.

SARS-CoV-2 remained viable in aerosols for the duration of the three-hour experiment. It was more stable on plastic and stainless steel than on copper and cardboard, with viable virus detected up to 72 hours after application to plastic and stainless steel. On copper, no viable SARS-CoV-2 was measured after four hours and no SARS-CoV-1 measured after eight hours. No viable SARS-CoV-2 was measured on cardboard after 24 hours and no viable SARS-CoV-1 measured after eight hours.

Both viruses had exponential decay in virus titer across all experimental conditions, the study found. The half-lives of both viruses were similar in aerosols, with median estimates of approximately 1.1 to 1.2 hours and 95% credible intervals of 0.64 to 2.64 for SARS-CoV-2 and 0.78 to 2.43 for SARS-CoV-1. The half-lives of the two viruses were similar on copper. On cardboard, the half-life of SARS-CoV-2 was longer than that of SARS-CoV-1. The longest viability of both viruses was on stainless steel and plastic; the median half-life of SARS-CoV-2 was approximately 5.6 hours on stainless steel and 6.8 hours on plastic.

“We found that the stability of SARS-CoV-2 was similar to that of SARS-CoV-1 under the experimental circumstances tested,” the researchers wrote in a letter to the editor published in the March 17 NEJM. “This indicates that differences in the epidemiological characteristics of those viruses probably arise from other factors, including high viral loads in the upper respiratory tract and the potential for persons infected with SARS-CoV-2 to shed and transmit the virus while asymptomatic.”

This makes disease control measures that were effective against SARS-CoV-1 less effective against the new coronavirus.

In an NIH press release, the researchers also noted that most secondary cases of SARS-CoV-2 seem to be occurring in community settings instead of healthcare settings. But “healthcare settings are also vulnerable to the introduction and spread of SARS-CoV-2, and the stability of SARS-CoV-2 in aerosols and on surfaces likely contributes to transmission of the virus in healthcare settings.”