The role of surfaces in COVID-19 spread

Although the one-year mark since the World Health Organization declared the COVID-19 outbreak a global pandemic passed last month, researchers from various disciplines of science say there is still much to learn about how the SARS-CoV-2 virus that causes COVID-19 operates. 

That is why two researchers recently combed through decades of studies regarding the ability of viruses to live on inanimate and inert objects. The research provides valuable insight for health care.  

Their findings, “Contamination of inert surfaces by SARS-CoV-2: Persistence, stability and infectivity. A review,” was recently published in the Environmental Research journal. The literature review includes dozens of studies mainly from 2020 and 2021, but also cites research on the viability of virus infectivity from surfaces that dates back to 1975 and the early 2000s. 

Much of the earlier studies focus on human coronaviruses similar to SARS-CoV-2, such as SARS-CoV-1. In regards to SARS-CoV-1, the researchers cited a study from March 2020, the early days of the pandemic, that found that SARS-CoV-1, MERS and endemic human coronaviruses could persist on inanimate surfaces such as metals, glass or plastic for up to nine days. 

Another 2020 study published results of an experiment testing surface stability of SARS-CoV-2 compared with SARS-CoV-1. The data consisted of 10 experiments involving both coronaviruses within five environmental conditions: on plastic, on stainless steel, on copper, on cardboard and traveling through aerosols. 

The researchers in this case found that SARS-CoV-2 was more stable on plastic and stainless steel. The median half-life was approximately six hours and seven hours on these surfaces, respectively. Copper and cardboard were less hospitable to the virus, with a median half-life of just one hour on copper and three on cardboard. Viable virus was detected up to 72 hours after application to these surfaces. 

Another study reported that the infection decay chart for SARS-CoV-2 showed a steady decrease in its infection capability over time, and depending on the surface: plastic (72 hours), stainless steel (48 hours), copper (four hours) and cardboard (24 hours).

The researchers who performed the literature review highlight that as more and more studies have been released regarding the virus causing COVID-19, it has become evident that close person-to-person contact and small aerosol respiratory droplets are the main transmission pathways for SARS-CoV-2. 

However, they also communicate three clear points about surfaces: Surfaces still represent a potential route of transmission even if they are not the main source; the virus can last on different surfaces from hours to days; and appropriate disinfection measures should decrease the risks of COVID-19.