/ sergei_fish13, stock.adobe.com
–
Bochum – The new SARS-CoV-2 coronavirus remains infectious on surfaces for long periods of time, even at higher outside temperatures. This was recently shown in the Journal of Infection (2020; DOI: 10.1016 / j.jinf.2020.05.074) published laboratory experiments.
SARS-CoV-2 is believed to be primarily transmitted via droplets and aerosols. However, transmission via objects or surfaces is not excluded. It could be particularly relevant in hospitals.
A team led by Stephanie Pfänder from the Ruhr University in Bochum has investigated how long the viruses remain infectious on surfaces. The researchers varied the surface temperature from normal room air to the refrigerator temperature (4 ° C) and the high summer 30 ° C.
The results contradicted expectations. The researchers had expected (or hoped) that summer temperatures would kill the virus faster. The opposite was the case.
The half-life, in which the number of infectious particles decreases by 50%, was the longest when heated to 30 ° C. at about 17.9 hours. At the refrigerator temperature, the half-life was 12.9 hours. Virus decay was fastest at room temperature with a half-life of 9.1 hours.
The experiments were carried out on dry surfaces. According to Pfänder, dryness reduces the infectivity of the viruses 100 times within the first hour. In the following 4 to 8 hours, the number of infectious particles initially hardly decreased and then continued to decrease slowly, albeit almost independently of the temperature.
Two other factors that could affect infectivity in summer were not investigated in the experiments. This was once the humidity. Previous studies had shown that the survival of corona viruses on surfaces at a high (80%) and a low (20%) humidity is significantly higher than at a medium humidity (50%). The UV light from the sun also has a killing effect on the viruses. © rme / aerzteblatt.de
– .
