Information from a new study led by scientists from the U.S. National Institutes of Health was released on March 13, 2020 as a letter to the editor and investigates the stability of the recent human coronavirus in aerosols and on surfaces made of plastic, stainless steel, copper, and cardboard. Formerly known as HCoV-19, the virus has now been named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The study evaluated the stability of both SARS-CoV-2 as well as the SARS-CoV-1 virus that spread in the years 2002 and 2003. In the letter written by the authors, the study is described as having evaluated the stability of both viruses to estimate their decay rates using a Bayesian regression model. The concentration (titer) of the viruses was measured in aerosols over three hours and on the materials over the course of seven days at environmental conditions maintained between 21 and 23°C at 40% relative humidity. Results are reported as the mean values from three replicates.
In aerosols, the virus was found to remain throughout the duration of the three-hour experiment. For surface materials, the study found that “SARS-CoV-2 was more stable on plastic and stainless steel than on copper and cardboard.” The virus was detected for up to 72 hours on plastic and stainless steel, up to 24 hours on cardboard, and the virus was not found on copper after four hours. The concentration of both viruses was found to exponentially decay, with median half-lives for SARS-CoV-2 estimated for plastic (6.8 hours), stainless steel (5.6 hours), and aerosols (1.2 hours). The study notes that individual replicate data for cardboard were significantly more variable than for the other materials, resulting in a greater standard error; this means, that the virus’ survival on cardboard may be longer or shorter than 24 hours. The shorter duration of its survival on copper is likely due to copper’s antimicrobial actions.
Overall, “the stability of SARS-CoV-2 was similar to that of SARS-CoV-1 under the experimental circumstances tested,” and the authors suggest that other factors may be responsible for the heightened spread of the virus as compared to SARS-CoV-1. This could include the high viral loads in the respiratory tract of infected persons, as well as the outcomes from a recent study from scientists at The University of Texas at Austin showing that more than 10% of cases result from contact with an infected person that does not yet have any symptoms.
While no research studies have been published yet specifically investigating the stability of the virus on packaging under real-world conditions and across the supply chain, the results from this study raise concerns that packaging may be playing an important role in helping to spread the virus. Noteworthy is that there is also currently no evidence for infection with the virus via packaging, however, based on the available evidence an abundance of precaution for this route seems appropriate. In addition to the recommendations being made by the World Health Organization (WHO) and local health authorities, the Food Packaging Forum is recommending consumers to consider either (i) washing all packaging immediately when it enters the household with soap and water, (ii) alternatively, transferring packaged goods from the packaging to cleaned containers for storage, and then discarding the packaging, or (iii) quarantining the items for up to three days in the household before touching them again. These recommendations apply to items bought in stores and delivered to homes, such as mail order groceries or meal delivery services, etc.
More information related to SARS-CoV-2 and packaging is available on the Food Packaging Forum’s resources page.
New England Journal of Medicine (March 17, 2020). “Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1.”
Science Daily (March 17, 2020). “New coronavirus stable for hours on surfaces.”
EurekAlert (March 17, 2020). “New coronavirus stable for hours on surfaces.”
Science Daily (March 16, 2020). “Coronavirus spreads quickly and sometimes before people have symptoms, study finds.”
CNN Health (March 16, 2020). “Infected people without symptoms might be driving the spread of coronavirus more than we realized.”
Van Doremalen, N. et al. (March 13, 2020). “Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1.” Pre-print doi: 10.1101/2020.03.09.20033217
Du, Z. et al. (March 13, 2020). “The serial interval of COVID-19 from publicly reported confirmed cases.” Pre-print doi: 10.1101/2020.02.19.20025452