Coronavirus may survive on outdoor surfaces for longer in autumn, US study suggests
- Researchers find it could linger for up to a week outside in lower temperatures and humidity – more than the one to three days in summer
- That could ‘potentially contribute to new outbreaks’ in northern hemisphere, they warn in non-peer-reviewed paper
Researchers found that in lower temperatures and humidity, the virus could, for example, remain on a hiker’s jacket if it was outside for a week – and remain infectious for that time – whereas in summer its lifespan was estimated to be one to three days.
The prolonged survival of the virus on surfaces in autumn could “potentially contribute to new outbreaks”, the team led by Juergen Richt, professor of veterinary microbiology at Kansas State University, wrote in a non-peer-reviewed paper posted on preprint website bioRxiv.org on Monday.
They believed the virus would also survive for longer indoors in colder and less humid conditions. The study found it had an average half-life – or rate of decay – of nearly eight hours on a stainless steel doorknob, or nearly 10 hours on a window, which was about to twice the duration in summer.
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The coronavirus, which causes the disease Covid-19, has adapted well to humans. But to survive outside its human hosts – it spreads through respiratory droplets and contaminated surfaces – the pathogen is believed to prefer lower temperatures and humidity.
For the study, Richt’s team used climate data from America’s Midwest to recreate artificial seasons in biosafety chambers. Temperature was controlled at 13 degrees Celsius and 66 per cent relative humidity for spring and autumn, while for summer it was kept at 25 degrees and 70 per cent.