This is what you must know about COVID-19 and the winter months

Two weeks back, a paper published in the Journal of Hospital Medicine itemized the reasons COVID-19 deaths and hospitalizations were on the decline in the US:

  1. Health systems are getting better at anticipating severe presentations of the disease
  2. Clinicians are getting better at administering effective therapeutics
  3. The American public is getting better at adhering to public health officials

Despite all three of these things still being statistically true, critical COVID-19 cases are surging exponentially and the national death rate is currently around 232,693.

“The U.S. recorded another 91,500 new cases of the coronavirus on Tuesday, the second-highest single-day tally to date, according to Johns Hopkins data. The seven-day average of daily new cases now stands at 86,362 — 20% higher than last week’s levels,” CNBC reports.

The mechanisms facilitating these swells are halved between administrative missteps and seasonal changes. Holidays sort of functioned as an inflection point for both.

Social distance easing was initially pitched as a premium for counties able to keep their cases down. Some state officials even assigned specific numbers to this objective.

But then being honest about the coronavirus became electorally unpopular. So Ruby Tuesdays stayed open and our grandparents got to play Parcheesi with Greta Garbo.

More than that though is the data that keeps challenging what we thought we knew about transmission risk.

During the summer months, we felt comfortable outdoor dining and attending limited capacity events because virologists seemed confident that SARS-CoV-2 is less stable in warmer temperatures. The same is comparably true with respect to the six-feet distance rule.

In a report published in March, Qasim Bukhari and Yusuf Jameel, of the Massachusetts Institute of Technology, analyzed global cases of COVID-19, and found that 90% of infections are transmitted in areas that are between 37.4 and 62.6 degrees Fahrenheit (three to 17 degrees Celsius) and with an absolute humidity of four to nine grams per cubic meter g/m3 (which is a calculation of moisture in the air irrespective of temperature.)

The SARS virus that caused the epidemic of 2002 and the MERS virus that staffed the outbreak of 2012 both ended up being acutely seasonal, with transmission rates peaking between January and May.

So the data supports seasonal suppression just not as faithfully as initially presumed.

In a study published more recently in the International Journal of Environmental Research and Public Health, its co-authors, Sajad Jamshidi, a research assistant at Purdue University, and Maryam Baniasad, a doctoral candidate at Ohio State University explored the other relevant parameters.

According to their findings, mobility plays a monumental role in seasonal surges.

In fact, trips and spending time away from home accounted for 34% and 26% of the contributing factors respectively. These were followed by population (23%) and urban density (13%).

“Prior evaluations of the relationship between COVID-19 and weather indicate an inconsistent role of meteorology (weather) in the transmission rate. While some effects due to weather may exist, we found possible misconceptions and biases in the analysis that only consider the impact of meteorological variables alone without considering the urban metabolism and environment,” the authors wrote in the new paper. “Our findings highlighted the importance of considering spatial and temporal scales for interpreting the weather/climate impact on the COVID-19 spread and spatiotemporal lags between the causal processes and effects. On global to regional scales, we found contradictory relationships between weather and the transmission rate, confounded by decentralized policies, weather variability, and the onset of screening for COVID-19, highlighting an unlikely impact of weather alone.”

Even if colder months increase transmission risk, officials should prioritize public health practices, given they are doing much more of the leg work as far as surging cases are concerned.

“We shouldn’t think of the problem as something driven by weather and climate,” the authors continued in media release. “We should take personal precautions, be aware of the factors in urban exposure.”

“The effect of weather is low and other features such as mobility have more impact than weather. “In terms of relative importance, weather is one of the last parameters.”

Researchers also expanded data on distance risk in the journal Physics of Fluids. Not only can a single 100-micrometer cough droplet travel up to 6.6 meters (about 21.65 feet) with wind speed of two meters per second but the droplets can travel even further under dry air conditions because of droplet evaporation.

“In addition to wearing a mask, we found social distancing to be generally effective, as droplet deposition is shown to be reduced on a person who is at least one meter from the cough,” says study author Dr. Fong Yew Leong, also from A*STAR Singapore. “The ongoing COVID-19 pandemic has led many researchers to study airborne droplet transmission in different conditions and environments. The latest studies are starting to incorporate important aspects of fluid physics to deepen our understanding of viral transmission.”


Both new reports strengthen social distancing and mask awareness by weakening academic consensus. In other words, because everything we thought we knew about the coronvirus can be overturned at any moment, it’s best to spend every moment eliminating any and all risks.