Obese or otherwise, we want to keep children from contracting COVID-19, and if they do catch it, we want them healed quickly and thoroughly. This blog has mentioned the legal and logistical factors that come into play when testing and contact tracing, amongst minors, are at issue. Because of the disease’s long incubation period and additional logistical delaying factors, any statistics we see are only a picture of how conditions were a few weeks ago, not now.
Our knowledge of the first version of SARS-CoV-2 is far from complete, and it keeps changing as if it wants to make sure we never catch up. And of course over in Nature’s camp, other factors are also at work. At one point in 2020, claims were made that the arrival of hot weather would cause the virus to dry up and blow away, which was neither literally nor figuratively true.
Figuring it out
In March, a small Chinese study concluded that the virus “showed no signs of weakening in warm and humid conditions.” In June, at the University of Sydney, researchers “discovered a 1 percent decrease in humidity could increase the number of COVID-19 cases by 6 percent.” Epidemiologist Professor Michael Ward explained it to the press like this:
When it comes to climate, we found that lower humidity is the main driver here [Australia], rather than colder temperatures… It means we may see an increased risk in winter here, when we have a drop in humidity. But in the northern hemisphere, in areas with lower humidity or during periods when humidity drops, there might be a risk even during the summer months.
What are the biological implications regarding the airborne virus, which is a living organism? In humid air, apparently, aerosols are bigger and heavier (and sometimes called droplets), so they fall to the ground or other surfaces more quickly, rather than floating around. Dr. Ward says,
When the humidity is lower, the air is drier and it makes the aerosols smaller. When you sneeze and cough those smaller infectious aerosols can stay suspended in the air for longer. That increases the exposure for other people.
Results were published of a multi-author study of conditions in 50 cities, of which eight were heavily affected by COVID-19:
The 8 cities with substantial community spread as of March 10, 2020, were located on a narrow band, roughly on the 30° N to 50° N corridor. They had consistently similar weather patterns, consisting of mean temperatures of between 5 and 11 °C [41º – 51.8º Fahrenheit], combined with low specific humidity (3-6 g/kg) and low absolute humidity (4-7 g/m3).
In the same month, Chelsea Harvey summed it up for Scientific American:
Several laboratory experiments have suggested higher temperatures and humidity are associated with reduced survival of the virus. That said, the report noted, conditions simulated in the lab don’t always mimic conditions the virus will encounter in real life.
Your responses and feedback are welcome!
Source: “Coronavirus shown to spread in high heat and humidity,” News-Medical.net, 03/30/20
Source: “Reduced humidity linked to increased COVID-19 risk,” MedicalXpress.com, 06/01/20
Source: “Temperature, Humidity, and Latitude Analysis to Estimate Potential Spread and Seasonality of Coronavirus Disease 2019 (COVID-19),” JAMANetwork.com, 06/11/20
Source: “Summer Weather Won’t Save Us from Coronavirus,” ScientificAmerican.com, 06/19/20
Image by Jernej Furman/CC BY 2.0