HealthWorld

In Sydney, Australia, the start of winter brings fear of a spreading virus

Winter is coming south of the Equator, along with predictions of the coronavirus’s spread

As countries in the Northern Hemisphere tilt into summer and emerge from months-long coronavirus shutdowns, winter arrives this month in subtropical parts of the Southern Hemisphere – and with it increased concern for the spread of the virus.

Studies of how the novel coronavirus behaves from season to season are still in their early stages. Preliminary results show that temperature and other climatic factors have less impact on its spread than social behaviour and the accompanying restrictions that governments put in place.

But researchers in Australia, Southern Africa and South America say colder weather is cause for significant concern.

“We need to be thinking if it’s wintertime, it could be COVID-19 time,” said Michael Ward, an epidemiologist in the University of Sydney’s School of Veterinary Science, in a statement. Ward and colleagues published a paper on Tuesday which found that every 1% decrease in humidity increased coronavirus cases by 6%. Australia’s winters are generally less humid than its summers, though the degree depends on the region.

Summer weather could help fight coronavirus spread but won’t halt the pandemic.

Humidity is just one of many seasonal climatic, biological and behavioral variations that researchers have been investigating.

Bad timing

Humidity interacts with temperature as well as ultraviolet rays, for instance, and heat and UV exposure are also postulated in some ongoing studies as potential suppressors of the virus’s spread. Others are examining how those climatic factors may be confounding variables, with altitude possibly being a more important measure.

Parts of South America in the Southern Hemisphere tend to be less humid during their upcoming winter months, which has researchers in Brazil, the world’s biggest coronavirus hot spot, worried.

While much of the country is tropical, its southern plains dry out during winter, and temperatures can drop below freezing.

“The United States was lucky in that it started amassing cases at the end of its winter, and the start of spring,” said Mauro Sanchez, an epidemiologist at the University of Brasília. “Our cases are growing as winter approaches. The timing was not ideal.”

Rife in a cool climate

Temperature-wise, the coronavirus “seems to be spread at maximum rates when daily mean temperatures are in the 5 to 11°C range [41 to 52 degrees Fahrenheit], and rate decreases steadily as the temperature rises”, according to a statement by South Africa’s government-funded Applied Centre for Climate and Earth Systems Science.

Those climatic factors affect how our bodies function and how susceptible they may be. For instance, Bob Scholes, professor of systems ecology at the Global Change Institute of the University of the Witwatersrand in Johannesburg, said that in cold weather, mucus tends to form at the tip of the nose, which may promote inhalation of infected droplets, as it does with influenza and the common cold.

Then again, cold but humid weather may mean that vector droplets containing the coronavirus are larger and heavier, and therefore more likely to fall to the ground than circulate in the air and be breathed in.

Source
Washington Post
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Henry Cobblah

Henry Cobblah is a Tech Developer, Entrepreneur, and a Journalist. With over 15 Years of experience in the digital media industry, he writes for over 7 media agencies and shows up for TV and Radio discussions on Technology, Sports and Startup Discussions.

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