Coronavirus survives on surfaces for 28 days in lab conditions, study reveals

A study carried out by Australia’s national science agency found that SARS-CoV-2, the virus responsible for Covid-19 infection, can remain infectious on surfaces like phone screens, stainless steel and banknotes. The findings give a startling contradiction to earlier belief of survival period of the novel coronavirus, which was thought to survive for a shorter duration on surfaces.

The experiment, however, was conducted in dark in laboratory settings. Earlier studies have also revealed that UV light can potentially kill the virus. Furthermore, the coronavirus is believed to be transmitted through coughing, sneezing, and talking while in proximity. Some experts are also skeptical about the real threat of surface transmission in real life settings. But recent studies have put a lot of confirmatory weight on the virus being airborne, i.e., spread by particles suspended in the air. The US Centers for Disease Control (CDC) has also relayed possibility of someone getting infected with the coronavirus on touching an infected surface. However, the possibility is believed to be very low.

What does the study reveal?

The previous tests in laboratory settings had found that SARS-CoV-2 can remain active and survive for 2-3 days on surfaces like glass and banknotes, and for up to 6 days on stainless steel and plastic. But the latest research study by Australian agency CSIRO found virus to be “extremely robust” and can survive for 28 days. This period was found to be on smooth surfaces like glass on mobile phone screens, and plastic and banknotes. The study was done by keeping the surfaces at 20C or 68F, that is near room temperature and in dark. In contrast, the flu virus is able to survive for 17 days in similar conditions.

The study was published in Virology Journal. It also found that the novel coronavirus survived for shorter duration at higher temperatures as compared to cooler temperatures. The virus was found non-infectious within 24 hours on some surfaces at 40C temperature. Virus also stayed active for longer duration on surfaces that were smooth, non-porous as compared to those that were porous like cloth and could not transmit virus past 14 days.

Disagreements on the study

The study was however criticized by Common Cold Centre, Cardiff University’s former director Prof Ron Eccles. He said that the revelation of virus remaining active for 28 days is bound to cause “unnecessary fear in the public.” He said, “Viruses are spread on surfaces from mucus in coughs and sneezes and dirty fingers and this study did not use fresh human mucus as a vehicle to spread the virus.”

“Fresh mucus is a hostile environment for viruses as it contains lots of white cells that produce enzymes to destroy viruses and can also contain antibodies and other chemicals to neutralize viruses. In my opinion infectious viruses will only persist for hours in mucus on surfaces rather than days.”

Inference we can extract

The study, if anything, highlights and further stresses on the need of cleaning hands and disinfecting surfaces like our mobile touchscreen. We know that Covid-19 spreads through air particles and the virus remains infectious for over three hours in airborne particles. Regular cleaning and disinfecting surfaces is more important than ever to curb the spread of SARS-CoV-2 virus.