The terror of coronavirus disease 2019 (COVID-19) pandemic is sweeping across the world. As of today (December 8, 2020), global cases of COVID-19 reached 67,591,203 with 1,544,533 victims [
1]. Korea is dealing with this dreadful contagion relative well and the cumulative cases of COVID-19 is 38,755 with 552 deaths as of today [
2]. However, Korea is also experiencing the third wave of COVID-19 peak since middle of November. The problem is that we are entering the winter season. There are gloomy predictions that mass migration and reunion of family members for the celebration of Christmas and the end of year would lead to the explosion of new cases of COVID-19 in the January of next year [
3]. More worrisome is the fact that winter is also the season of influenza in the Northern hemisphere. COVID-19 and influenza share similar symptomatology, making differential diagnosis very difficult. The protracted hospital admissions and a higher risk of mortality of COVID-19 could potentially make the forthcoming northern hemisphere influenza season a public health catastrophe [
4]. We might experience an unexperienced, mixed pandemic by COVID-19 and influenza, so called double-demic. Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said regarding influenza vaccination in the era of COVID pandemic that “Get the flu shot! So that you could at least blunt the effect of one of those two potential respiratory infections.” The symptoms of COVID-19 vary widely from asymptomatic infection to severe sepsis. However, fatal cases of COVID-19 are almost exclusively caused by severe pneumonia and even non-critical pneumonia survivors of COVID-19 suffered significant impairment in diffusion capacity and quality of life after being discharged from hospital [
5].
In this context, it is well-timed that the special issue of Tuberculosis and Respiratory Diseases was published in December. The special issue contains an article regarding COVID-19, “Risk factors for mortality among hospitalized patients with COVID-19. An overview in Mexican population” [
6]. Preexisting respiratory diseases, specifically COPD, and smoking were associated with grave outcomes in COVID-19 cases [
7]. Important opinions regarding major respiratory diseases such as tuberculosis, chronic obstructive pulmonary disease, ozone associated lung injury, and lung cancer, which are also major risk factors for COVID-19 were covered in review articles and original papers of this special issue. I hope this special publication would be helpful for understanding and dealing with COVID-19 pandemic that we are desperately going through.