How Climate and Seasonality Affect Viral Contagion

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Seasonality

Along with misinformation about how COVID-19 is spread, we are all learning a new vocabulary.

It is useful and assuring to know the fundamental language. We have all learned “social distancing,” “flatten the curve,” and “Personal Protective Equipment, (PPE)”.
Seasonality, or how an outbreak responds to warmer weather, is one term with which to become familiar. Warm weather is not a miracle or a cure but it does impact outbreaks.

We have warmer conditions due to climate change. In some places, this means a longer flu season. In other places, it means changes in animal migration, pollen, and freak weather. Warmer, wetter weather means that droplets of moisture — including coughs, sneezes, and breathe — fall out of the air sooner. In drier climates, our droplets don’t.

The COVID-19 virus is suspended in droplets and usually transmits as an aerosol or airborne particles. This means that dry air lets those droplets travel further; in humid air, they don’t travel as far. A droplet that becomes heavy falls more quickly to the ground. It is not wonderful to have contaminated droplets on the ground or any surface but it is a good deal better than having them travel easily from one person to another.

A Little Knowledge

In the news, there is still some fundamental confusion about things we all need to know — yesterday. It is more important than ever to know how and why an infection can spread.

A very good, intelligent friend of mine, for example, thought that as we see so much disinfecting of surfaces, that this was a major source for contamination. Yes, by all means, disinfect surfaces, but don’t let the constant videos of wiping mania let you think that the virus prefers any surface more than a warm, human body. When we hear a term like “social distancing,” it does not always emphasize that the reason we do it. It is because a host most often spreads germs to another host. In other words, a coronavirus wants a body to live in.

Seasonality also speaks to staying indoors. Most researchers believe that we spread host-to-host germs more readily when we congregate indoors. We call it colds and flu season because we are driven indoors by colder weather and, once inside, we are more exposed to germs.

We gather together and breathe the same air. When the weather gets warmer, there is more chance for fresh, clean air. There is more opportunity for sunlight, which “modulates bacterial communities” and “inactivates [some] viruses,” but it’s not yet known if sunlight is effective on coronavirus. Stay aware of pollen and other allergens if you have sensitivity, as these do increase with a warming climate.

Go outside if you can.

Another friend was depressed at having to stay indoors. He thought it was too risky to be outside. It is only risky to be outside in crowds, or where air quality is poor. (Bad air quality, of course, is yet another consequence of pollution and a changing climate). Exercise itself boosts immunity, in addition to helping one not succumb to going stir crazy by being cooped up inside. During this pandemic, check your state and municipal government restrictions before going outside.

If allowed, it is also good to spend time outdoors even when the weather is cold if you take precautions. Just remember that the drier the air, the farther airborne particles can travel. Cold air also contributes to contagious illness because when our mucus membranes dry up, the natural filter they provide is lost. Personal hygiene rules apply, of course.

We’re all a bit distracted

Common sense as we have all been taught is useful, but it is easy to be forgetful and distracted. We are social creatures, and habits die hard.
Remember that a person who has no signs or symptoms can still carry a virus. Elbow bumps are the new norm instead of a handshake or hug for this reason.
We are all in this together, even as we keep our distance.

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Previously published on Medium.com

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