By: Christopher Sirota, CPCU
The Centers for Disease and Control and Prevention (CDC) explains that SARS-CoV-2 is the virus that causes the COVID-19 disease. The CDC notes that transmission of the virus is mainly airborne from person to person; however, transmission is also possible from contaminated surfaces.
Back in March 2020, the U.S. Environmental Protection Agency (EPA) issued a press release describing some cleaning products that should effectively kill the SARS-CoV-2 virus on hard surfaces.
Now, according to a CSIRO press release, researchers at the Australian Centre for Disease Preparedness (ACDP) have examined, in lab conditions, how long the SARS-CoV-2 virus, can survive on various fomites - surfaces that can transmit disease. (Full report available here)
The researchers reportedly applied droplets of SARS-CoV-2 in artificial mucus on the following surfaces: stainless steel, glass, polymer banknotes, paper banknotes, cotton, and vinyl. The study reportedly measured the subsequent potential viability of the droplet after several time periods, at 50% humidity and at three temperatures (20 C/78 F, 30 C/86 F, 40 C/104 F). The experiment was also conducted in the dark, reportedly to avoid the potential impact of UV light.
Per the press release, the researchers found that the virus:
- "survived longer at lower temperatures
- tended to survive longer on non-porous or smooth surfaces such as glass, stainless steel and vinyl, compared to porous complex surfaces such as cotton
- survived longer on paper banknotes than plastic banknotes."
(Click here for an infographic of the results)
Researchers reportedly expressed concern that SARS-CoV-2 could be viable for at least 28 days at room temperature on smooth surfaces such as stainless steel--common in hospitals, and glass--found on smartphones and ATMs. SARS-CoV-2 actually seems to be more resilient on such fomites than Influenza A which, in tests, only survived for 17 days in similar circumstances, the press release explains.
To be clear, the study reportedly does not provide insight into how much surface contact and viral load is needed to infect a person but does seem to support mitigation efforts that include hand washing and surface cleaning. Per the report, studies on other viruses have shown that "[f]omite transmission [is a] highly efficient procedure, with transmission efficiencies of 33% for both fomite to hand and fingertip to mouth transfer for bacteria and phages."
The report also notes that the results seem to be in line with other studies that have shown that SARS-CoV-2 can survive on hospital PPE for up to 21 days "on both plastic and N95 mask material when held at room temperature."
Outside the Lab: Some Potential Good News About Transmissibility
A separate group of researchers apparently has been concerned with fomite transmission of the coronavirus, except this time the study occurred outside the lab.
The Lancet has reported that researchers have tried to determine the risk of fomite transmission in a real-life hospital setting. According to the article, the researchers swabbed surfaces in a hospital in Northern Italy, and were unsuccessful at culturing contaminated swabs. The researchers reportedly concluded that the results:
suggest that environmental contamination leading to SARS-CoV-2 transmission is unlikely to occur in real-life conditions, provided that standard cleaning procedures and precautions are enforced. These data would support [the] point that the chance of transmission through inanimate surfaces is less frequent than hitherto recognised.