Surfaces at a Mount Wellington coolstore have been tested for COVID-19 in an effort to uncover the route of a COVID-19 outbreak in the community. The possibility of the virus coming from an overseas freight arriving at the coolstore is being investigated.
It would appear that COVID-19 thrives in cold temperatures. Surface transmission is considered a lower risk for virus transmission than person-to-person contact. Cold environments, such as meat works, however, have been at the centre of clusters overseas. Studies have been done on how long the virus can survive on different surfaces. Traces of the virus were detected on plastic and steel up to three days after contamination and on cardboard for up to one day.
In cold conditions, the virus can survive longer. One study looking at the survival time in a test tube found at 4C, the virus survived for 14 days. At 37C it lasted just one day. None of these studies, however, are akin to real life situations and experts are weary of the risk of surface transmission being exaggerated.
The risk is considered low, but it’s still a possibility. No sunlight and cold conditions do extend the life of the virus and cold work environments have been at the centre of outbreaks in other countries. An abattoir in Germany was closed after 1500 workers were infected and in Melbourne at least three abattoirs were closed after outbreaks occurred. Abattoir-related outbreaks have also occurred in the United Kingdom, France, Brazil, Denmark and the Netherlands.
There are different factors at play in these situations. Physical distancing on a production line can be hard, background noise can mean shouting is needed to communicate, increasing the risk of droplet spread, and air filtration systems push air around, potentially spreading droplets further.
The conditions at the New Zealand coolstore facility where cases have emerged are not the same as overseas abattoirs but it seems that there's a chance that cold may play a role in giving any virus in the environment a chance to live longer.