CHARLOTTE, N.C. (WBTV) - Many have questions on how weather might play a role in the spread of COVID-19.
COVID-19 is a novel coronavirus. The “novel” part means not previously identified.
Months have passed since the first case was announced and still there are a ton of unknowns – including its exact origin.
According to the Centers for Disease Control, it’s caused by a coronavirus. Coronaviruses are a large family of viruses that are common in people and different animals that include camels, cattle, cats and bats.
Early on, the CDC reports many of the people infected at the epicenter of the outbreak, in Wuhan, China, were linked to a large seafood and live animal market; however later on a large number of patients did not have exposure to live animals.
But what role does weather play, if any?
At the time of the outbreak’s peak in Wuhan, between January and February, temperatures were in the 40s and 50s. Last week, highs there were reported in the 70s.
So, one could in theory deduce that while temperatures have consistently risen, new cases of the virus have consistently fallen.
There are studies suggesting warmer temperatures and higher humidity can help slow the spread. Some experts say increased ultraviolet light from the sun, as summer approaches, could help.
A recent report from AccuWeather compared the per capita infection rates of Iceland, where Winter just ended last week, with Australia, where Summer just ended.
As of Tuesday, Iceland’s rate was 0.1777% or 648 cases in a population of 364,260. Australia’s rate was 0.0083%, or 2,044 cases in a population of 25.4 million people. By this comparison, Iceland’s infection rate is 22 times higher.
While not all infectious disease experts and epidemiologists agree warmer temperatures will slow the spread, Dr. Anthony Fauci of the National Institute of Allergy and Infectious Disease, referenced weather when warning of a possible second cycle during the Coronavirus Task Force briefing at the White House yesterday.
“What we're starting to see now in the southern hemisphere in southern Africa and in the southern hemisphere countries is that we're having cases that are appearing as they go into their winter season. And if in fact they have a substantial outbreak, it will be need to be prepared that we'll get a cycle around the second time,” said Fauci.
So you can see, all of this suggests at least a small link to weather. But, it’s not as definitive as something like the flu.
In the United States, cold and flu season usually coincide with the Winter months. Influenza is actually an Italian word that is literally translated to mean "influence of the cold".
Here’s where the weather plays a pivotal role. When an infected person coughs or sneezes, they release tiny respiratory droplets that flow out around them.
Viruses are more stable in colder air and lower humidity because those conditions help the virus particles remain suspended in air longer, meaning there’s a greater chance for contact with other people. Conversely, when the weather is warmer and there’s more moisture in the air, the droplets pick up water, grow larger and fall to the ground sooner.
When it comes to COVID-10, the droplets associated with the virus tend to be larger than other viruses, so they fall to the ground at a faster pace. Think of heavy thunderstorm rain versus mist and drizzle. That’s why the recommendation of social distancing is not set at any more than six feet.
Again, there are still many aspects of COVID-19 we just don’t know. We’re learning as we go. But there are some things we do know, and given the pattern, it’s reasonable to believe the virus spread will slow down as we warm up.
In the same way, it’s therefore not unreasonable to believe that it could spread south where Summer is on the horizon, just as the flu does most every year. And because so much is unknown, no one can predict whether the virus will return with such ferocity in the fall.
- Meteorologist Al Conklin