COVID epidemiology explained: COVID-19 and the winter months
November 30, 2020 4:45 PM
Eddie Gisemba, Director of Health Promotion for Students
With the cold days we can expect over the course of the next four months, we also anticipate a sharp increase in upper respiratory infections such as the common cold, seasonal influenza, and in 2020, COVID-19. This week, let’s briefly explore why the winter months bring an increase in cold/flu cases, why there is an added concern in 2020, and the reasons for policy changes to reduce spread.
Why the increase in cases?
Answering this question requires a review of the essential elements to infectious disease transmission; that is infectious agent, host, and environment. The infectious agent refers to the virus or bacteria that causes infection, the host is whoever gets infected, and the environment pertains to the relevant surroundings to facilitate a new infection. The winter months become a factor mainly for the infectious agent and the environment. The lower temperatures and humidity make infectious viruses such as the ones that cause colds and flus more resilient. The lower temperatures cause the fatty membrane that protects the virus and its genetic material to become more gel-like. This thickened layer enables the virus to thrive in these temperatures and increases the likelihood of it causing infection. The environment in the winter is modified because during the winter months we spend more time indoors. Thus, winter months are associated with more indoor dwelling, overcrowding, and air has less room to circulate. Changes in these two factors play a large role in the increase in upper respiratory infections in the winter.
Why the added concern in 2020?
It is possible for our health care infrastructure to be stretched even thinner during the winter months due to the COVID pandemic for a few reasons. One, there is a fair amount of overlap between the symptoms of COVID and other upper respiratory infections such as the cold and flu. This will increase the amount of screening and testing needed as we expect to see cases in the seasonal infections start to go up. It also raises a concern regarding self-diagnosis where mild cases of the COVID-19 assumed to be the flu and the increase in spread that can result. Two, hospitals will have to deal with more cases of the flu in addition to high numbers of COVID cases. Seasonal influenza results in an estimated 38 million cases, 400,000 hospitalizations, and 22 thousand deaths in the United States each year. Addressing the pandemic this winter will be more of a challenge since we’ll have to address peak levels of COVID cases along with the expected increases in other upper respiratory infections like influenza.
Winter 2020-21 recommendations
In anticipation for the winter months a number of population-level actions are being recommended. For instance, months ago COVID testing at the college was coupled with the annual flu shot. The primary goal with this measure is to reduce the number of cases of the flu and the associated outcomes which frees up time, energy and resources to focus on COVID. Other recommendations look to address COVID directly through scaling up mask mandates, potentially re-closing bars, restaurants, and gyms. Some states have opted for schools and colleges to go remote in the spring semester comparable to March 2019. This effort in particular aims to accomplish the same as last winter; further flatten the curve in order to not overwhelm the health care infrastructure. The benefit this time around is that we have promising vaccines that can be made available for the general public as of March/April 2021. If a vaccine is distributed in mid 2021 we hope that the end of the pandemic will be soon to follow.