(1) Cold, dry air irritates your nasal lining, and as a result, your nasal glands produce excess mucus to keep the lining moist. A runny nose and post nasal drip can occur.

Can this increase the risk of COVID-19 infection?

(2) According to a 2008 NIH research project, the answer could lie with the improved stability of phospholipids that encapsulate virus capsids in the winter. https://www.nature.com/articles/nchembio.77

(3) From Guinea Pigs with influenza, to a soup v. gel consistency of mucus and sputum, the NIH research points to a change in the physical properties of aerosols and fomites.

https://www.sciencedaily.com/releases/2008/03/080330203401.htm

(4) Virosomes appear to shield characteristic bond spectra of the underlying virus.

(5) Another article, published by the same authors about a month later provides even better evidence of lipid gel forming between 0° C and 10° C (32° F and 50° F).

(6) So at temperatures at or below 10° C (50° F), an ordered phospholipid micelle may encapsulate viruses and make them much more stable both as aerosols, fomites and perhaps even when suspended in sewer water (phospholipid micelles tend to float).

(7) Daily High Temperatures in Fargo, ND dropped from the mid 70° F range in early September, to 50° F by mid October.

Daily Case Rates have been rising since Trump's 4th of July at Mount Rushmore, through the Sturgis Motorcycle Rally, and have taken off with the colder weather.

(8) We are currently in MMWR Week 43. Influenza season usually onsets in five to six weeks.

(9) Another State seeing #COVID19 Case Rates skyrocket is Montana. The @Kinsa Prediction for Montana is shown below.

The recent rise seems to begin at the start of the third week of September, shortly after overnight lows dipped into the 30° to 40° F range.

(10) Remember indoor ventilation is key. Many heater systems do not use enough make-up air to ensure good ventilation.

Fomites may be much more critical due to increased viral stability at temperatures below 50° F (10° C).

Beware of things smeared by runny noses!