A capsid is the outer shell of a virus, which needs to be tough enough to hold and protect its contents in a passive mode, yet fragile enough to, at the right moment, enable the contents to rush out and fertilize the territory it has occupied. As a report on the subject explained,
[The] capsid also needs to become unstable to release the virulence factors into the host cell. Thus, the stability of the capsid and the transitions between stable and unstable structures are key issues in the life cycle of a virus.
What humans hope to do, of course, is end the virus’ lifecycle, with the purpose of ending the pandemic, and consequently preventing quite a lot of obesity. This is why researchers have shown interest in the weather, and in climate manipulation (on a micro-scale, like inside a room or a building). A recent post mentioned a few studies about humidity in this setting.
A very useful piece by Robert Roy Britt quotes experts like Lloyd Hough, Ph.D. While we may not have been aware that the Department of Homeland Security encompasses such an institution as the Hazard Awareness and Characterization Technology Center, it indeed does, and Hough is the head of it. With lower ambient temperature and humidity, he says, you get a stable virus. (This is why we see advisory labels on food packaging that say “Store in a cool dry place.” The environment encourages the containment of harmful critters.) When temperature and humidity rise, so does the threat posed by the destabilized virus.
Ajit Ahlawat, of Germany’s Leibniz Institute for Tropospheric Research, says,
If the relative humidity of indoor air is below 40%, the particles emitted by infected people absorb less water, remain lighter, fly further through the room, and are more likely to be inhaled by healthy people.
But the air is not the only factor. What about those healthy people on the receiving end of toxic aerosol? Their interior architecture certainly plays a role, Journalist Britt says,
Humidity not only affects the virus itself, but also the front lines of our immune system. From the nose on down, the human respiratory tract filters out particles that would do us harm. That filtering system and other aspects of our immune system don’t work as well in dry air, somewhat like how a dry sponge doesn’t clean as well as a wet one.
If someone wants to use a humidifier in the home, Britt offers caveats. The machines have to be cleaned quite conscientiously, and the filters need to be changed. Otherwise, it can create more problems. Some experts even go so far as to state that they do not recommend the use of a humidifier, period. Before proceeding, the author recommends consulting the relevant Mayo Clinic guidance.
Your responses and feedback are welcome!
Source: “Stability and Dynamics of Virus Capsids Described by Coarse-Grained Modeling,” ScienceDirect.com, December 2006
Source: “Why Some Experts Say Humidifiers Could Help Against Covid-19,” Medium.com, 11/08/20
Image by Mike Finn/CC BY 2.0