Can you get infected with coronavirus after using a shopping trolley in the supermarket? What about by touching a door handle in the office, or a remote control?
These are questions that many people have been asking since the coronavirus outbreak began.
Researchers have so far come to different conclusions on how long the virus can survive on surfaces. But now a team of scientists in Germany are trying to find answers.
“So far, no transmission of the virus in supermarkets, restaurants or hairdressers has been proven,” explained Bonn virologist Hendrik Streeck on the ZDF Markus Lanz talk show.
Instead, the major outbreaks have been the result of close get-togethers over a longer period of time, he said.
That's demonstrated in, for example, outbreaks that have stemmed from après-ski parties in Ischgl, at football matches in Bergamo or at carnival celebrations in the municipality of Gangelt in the Heinsberg district of North Rhine-Westphalia.
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Hotspot of Germany
Heinsberg is considered the epicentre of the corona outbreak in Germany after a couple infected with Covid-19 attended carnival celebrations there in February, leading to a large spread in the Gangelt area.
Figures from April 2nd for Heinsberg, which has a population of around 250,000, show the total number of confirmed cases at around 1,400 and 39 deaths. More than 690 people have recovered from the illness so far.
Streeck and a team of medical students have now set up a pioneering study in this area in a bid to shed light on how coronavirus spreads, and how it can be contained.
Over the coming weeks the Heinsberg district will be used as a real-life lab for this purpose.
Called the “Covid-19 case cluster study” and launched on Tuesday March 31st, the study will follow 1,000 people chosen because they are representative of the German population.
Streeck's team is “interviewing patients in order to identify possible causal chains with pre-existing conditions and to generate prevention recommendations for the entire German and European population,” reports the North-Rhine Westphalia state government.
Bonn virologist Hendrik Streeck. Photo: DPA
The scientists plan to go into homes, schools and hospitals and examine how the virus impacts everyday life, researching, for example, how it is spread through surfaces, mobile phones, door handles or TV remote controls.
There are high hopes that the results could be used to inform how the rest of Germany and beyond can deal with coronavirus in future.
Streeck said: “The Heinsberg district represents an ideal situation to find answers for the rest of Germany.”
No evidence of live viruses on surfaces
Initial surveys and investigations in homes in Heinsberg have already provided some indications of how the virus works.
Streeck, who is director of the Institute of Virology at Bonn University, said he was able to detect coronavirus by swabbing remote controls, washbasins, mobile phones, toilets or door handles.
However, it has not been possible to cultivate the virus in the laboratory on the basis of these swabs. “This means that we have detected the RNA (or ribonucleic acid, which carries the virus’s genetic information) of 'dead' viruses,” Streeck said.
According to his previous research results, he believes “that a door handle can only be infectious if someone has actually coughed in their hand and then reached for it.
“After that, you have to reach for the door handle yourself and touch your face,” he said. It is not yet possible to say how long the virus can remain on a door handle because not enough studies have been carried out.
Streeck added: “We were in a household where many highly infectious people lived, and yet we did not manage to detect a living virus from any surface.”
He said these early research results would now be further developed in the current study in Heinsberg.
Virologist Christian Drosten of Berlin's Charité hospital had also previously pointed out in an NDR podcast that coronaviruses are extremely sensitive to drying out. They are also transmitted by droplet infection and must be inhaled.
Therefore, according to the virologist, there is little chance of transmission by contact with notes or coins, for example.
Different findings on how coronavirus spreads
The Federal Institute for Risk Assessment (BfR) reports that the stability of coronaviruses in the environment depends on many factors such as temperature, humidity and the condition of the surface.
According to current findings, it is unlikely that imported goods such as food or consumer goods, toys, tools, computers, clothing or shoes could be a source of infection.
The BfR also emphasises that infection through contact with contaminated objects has not yet been proven.
Experts from the US Institute of Health NIH and the CSC, the epidemic control agency, however, had come to the conclusion that the coronavirus can survive for up to three days on plastics or stainless steel, 24 hours on paper and up to three hours in aerosols.
The Robert Koch Institute points out, however, that scientific studies on this topic are carried out under experimental conditions and don't reflect the realistic risk of transmission in everyday life.