Coronavirus could survive for longer in the fall without host, study finds

The virus's half-life on many outdoor surfaces in the fall is shown to be twice its length in the summer, and could potentially lead to further outbreaks.

Fall foliage is reflected in the water at Walden Pond in Concord, Massachusetts October 14, 2009 (photo credit: REUTERS)
Fall foliage is reflected in the water at Walden Pond in Concord, Massachusetts October 14, 2009
(photo credit: REUTERS)
The changing season may not do much to help stop the coronavirus pandemic in the northern hemisphere, as the virus may be able to survive on outdoor surfaces for much longer in the fall, according to a new US study, the South China Morning Post reported.
While the virus's lifespan on an outdoor surface without a host was estimated to be around one to three days in the summer, this does not seem to be the case in the fall. Rather, humidity and lower temperatures could allow it to remain alive and infectious for up to a week.
According to the study – which has not been peer-reviewed and was uploaded Sunday to bioRxiv – this is especially dangerous, as its more lengthy lifespan has the potential to lead to new outbreaks.
The study, led by Jurgen Richt of Kansas Sate University, artificially recreated climate conditions of the American Midwest in controlled laboratory settings to reflect both fall and summer. Coronavirus samples were then applied to the surfaces of 12 different materials and surfaces that people would come in contact with regularly. The result of this study showed a clear difference in lifespan between summer and fall, with the virus surviving longer in the summer.
Out of all the materials tested, the virus samples were able to survive for the longest period of time on Tyvek, which is a synthetic material used in a wide variety of products, including outdoor wear, PPE and insulation. On this material, the virus's rate of decay – or half-life – was a total of 45 hours. For comparison, its average half-life on a stainless steel doorknob was eight hours, and 10 hours on a window. This is approximately twice as long as its lifespan in the summer, according to SCMP.
The findings reflect claims made earlier in the crisis that the virus would not be able to survive for as long in the summer. Indeed, some experts and politicians had predicted that the outbreak could significantly slow down if not outright stop by summertime, as many diseases tend to be seasonal. However, this proved not to be the case, with the summer doing little to impact the pandemic.
In addition, the findings also reflect warnings made earlier in August by the US CDC, which stated that the pandemic could become much worse as the season shifts to fall, SCMP reported. At the time, CDC director Robert Redfield instructed people to “wear a mask, social distance, wash your hands and be smart about crowds.”
Likewise, Richt and his team agree, and urged people to prevent the further spread of COVID-19 by practicing “good personal hygiene and regular disinfection of potentially contaminated surfaces.”