The prospect of warm weather saving us all from a deadly pandemic is enticing. Is this a hope we can cling to?
Donald Trump tweeted hope that the virus would be contained as the weather starts to warm *1 Is this just wishful?
Well, in fact, viruses such as influenza and common cold do subside in warmer months! Illnesses do have “seasonality” in northern climates. So, yes, there is some scientific backing to this.
But to understand WHY and IF it applies to COVID-19 and this spring in particular I gotta drop a little bit of science facts on you so bear with me. Actually if you can follow along and understand the basic structure of corona viruses then you will know the answer to these major questions:
Does warm weather kill the virus?
Do sun rays kill the virus?
What cleaners / detergents / soaps are best?
How long does it last in/on: air, doorknobs, packages?
Some viruses have envelopes around them. The envelope surrounds the virus like a capsule to protect all its RNA (coding) from spilling out. Think of a gel capsule around Advil, but on a micro, micro level. This envelope is a gel membrane made up of fats. We call the fats lipoproteins. Lipoproteins (fats) are actually stolen from the host’s (human) cell membrane or the covering of our own cells. See, as a virus leaves its host (human) it bursts through our cell walls and takes a piece of our cell membrane wall with it and wraps itself up in it and this becomes its envelope! Like everything in nature the envelope gives the virus an advantage in disadvantage.’
- Advantage – It is a camouflage. Our immune system can’t recognize the virus before it infects us (because it’s wrapped in our own cell membrane).
- Advantage #2 – It can quickly attach to our human cells and merge into us because it literally has the same material as our cells.
- Disadvantage – The envelope is very susceptible to being broken. Once broken the virus cannot survive.
So bottom line – Enveloped viruses can easily evade our immune system and infect our cells but they can’t survive outside of the body long because the envelope will break. (And many things can break that flimsy envelope) HINT HINT – target this weakness.
So here is how the structure of the envelope can be exploited. It’s fats, right? So imagine a micro thin sheet of fat: like the thinnest shaving of butter surrounding a tiny fish. Once exposed to the air the tiny fish will immediately die. How do we break down that butter wall and let the tiny fish die?
Well…What breaks down fats like butter or lard or congealed grease? Heat or soap – right? Same with the envelope around the corona virus or influenza.
It prefers to be cold. It prefers to be dry.
So let’s answer all the questions above, armed with this knowledge.
- Does the warm weather decrease the virus?
- Warm humid air can decrease the spread of a virus.
- There is actually some evidence in retrospective studies on COVID-19 itself that it doesn’t spread as well in warm weather *6.
- Do sun rays kill the virus?
- What cleaners / detergents / soaps are best?
- Soap and water is the best! Grandma’s bar of soap is the best weapon to break the easy hydrogen bonds of the envelope membrane. Alcohol sanitizers work too. But, it must be the right concentration and time. 60-80% alcohol. Plus you must give alcohol time to desiccate or evaporate and dry. It is this action that breaks the envelope not the initial contact. These crazy pictures of cities spraying down parks with bleach are very unnecessary measures. Alcohols and soaps or even acids (like your stomach juice) break down fats better than a base (like bleach).
- How long does it last in/on: air, doorknobs, packages?
Now, viral transmission depends on two things: host behavior and virus structure.
Host behavior may be more important.
In order to apply the seasonal spread information to the current coronavirus pandemic we have to take one more lesson from seasonal influenza.
Human interactions change in northern climates during the winter. School, indoor events, bars… we do life indoors and in proximity to each other in winter. These factors give viruses an opportunity to find new hosts while the cool dry environment is optimal for its transmission.
So as we considered the external elements that impact coronavirus above, it is just as important to consider host behavior. In fact, host participation in the transmission process is the only thing we have control over! So while it is wonderful to know about the virus’s structure and behavior, I believe education about our behavior in this pandemic is the most important.
Do not give the virus what it needs to spread.
It relies on you and I in order to spread.
Do your part.
…But at least now you know how to clean and kill COVID-19 when it is outside your body.
- Trump Tweet. https://twitter.com/realDonaldTrump/status/1225728755248828416?s=20
- Influenza in heat and environment. https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.0030151
- UV Rays on viruses https://pubs.acs.org/doi/10.1021/es3036913
- UV Rays on Influenza https://www.nature.com/articles/s41598-018-21058-w
- COVID on surfaces NEJM https://www.nejm.org/doi/10.1056/NEJMc2004973
- COVID19 growth in various climate changes https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3551767