COVID-19 may survive longer and spread more in colder climates
For the Northern Hemisphere winters are almost here and with it comes the speculations of how the pandemic might take a turn. Since most respiratory diseases including cold and flu spread quickly in winters, some experts have indicated that COVID-19 cases may also increase with a drop in temperature and humidity.
In fact, various studies have shown that SARS-CoV-2, the causative agent of COVID-19, may survive longer and hence will be able to spread more in colder climates.
However, scientists have not yet reached a consensus about the association between changes in weather and transmission of COVID-19.
Controversial evidence:
A study conducted earlier by Harvard University early this year suggested that there was no link between changing temperature and COVID-19 transmission. The World Health Organisation had said that the infection can spread at any temperature. A study done in China indicated that SARS-CoV-2 may spread quickly in summers when the temperature is around 19 degrees Celsius and the relative humidity is at about 75%.
A systematic review published in the journal PLOS One indicated that warm and wet climates are not conducive to the spread of COVID-19 and that the virus would spread better in cold and drier climates. But the authors said that the temperature and humidity are not the only variables that determine the transmission of the disease.
One more study conducted in India also found that more cases of COVID-19 are seen in areas at a relatively higher altitude and colder temperatures
This might not be true:
Earlier in September, a study conducted at the American University of Beirut in Lebanon suggested that COVID-19 may become seasonal but only after the world achieves herd immunity against this infection. This is because a major proportion of the world’s population is susceptible to the disease right now, the virus will keep on spreading quickly. However, when a majority of people are immune to the disease, SARS-CoV-2 would not be able to jump hosts as effectively.
As per the study, several factors drive the spread of a viral infection. These mainly include environmental factors like temperature and humidity and host factors.
Experts suggested that at lower temperatures, viruses like COVID-19 stay stable for a long because of the improved stability in their lipid envelope.
Additionally, less humidity leads to quick evaporation of respiratory droplets which then stay in the air for longer.
Now regardless of the temperature effects on the disease, it is best to keep following all the precautionary measures such as social distancing, face masks, and use of sanitizer.
