A Pandemic Lesson for Global Lung Diseases: Exacerbations Are Preventable

Abstract

A dramatic global reduction in the incidence of common seasonal respiratory viral infections has resulted from measures to limit the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the pandemic. This has been accompanied by falls reaching 50% internationally in the incidence of acute exacerbations of preexisting chronic respiratory diseases that include asthma, chronic obstructive pulmonary disease, and cystic fibrosis. At the same time, the incidence of acute bacterial pneumonia and sepsis has fallen steeply worldwide. Such findings demonstrate the profound impact of common respiratory viruses on the course of these global illnesses. Reduced transmission of common respiratory bacterial pathogens and their interactions with viruses appear also as central factors. This review summarizes pandemic changes in exacerbation rates of asthma, chronic obstructive pulmonary disease, cystic fibrosis, and pneumonia. We draw attention to the substantial body of knowledge about respiratory virus infections in these conditions, and that it has not yet translated into clinical practice. Now that the large scale of benefits that could be gained by managing these pathogens is unmistakable, we suggest that the field merits substantial academic and industrial investment. We consider how pandemic-inspired measures for prevention and treatment of common infections should become a cornerstone for managing respiratory diseases.

Keywords: COPD; SARS-CoV-2 pandemic; asthma; nonpharmaceutical interventions; pneumonia.

Figure 1.

Major microbial factors in acute respiratory episodes. To the left of the figure, the circulation of multiple respiratory viruses in the population provides a continued source of mucosal insults. Circulation and adherence of common bacterial pathogens has the potential to cause invasive disease and sepsis as well as lower-grade chronic damage. Airway commensals also circulate within the population, and their diversity is protective against infection. Viruses and bacteria interact positively and negatively within the mucous layer and the epithelium. The microbiota and epithelia induce reactive immunity to infection and consequent inflammation, shown on the right. Current therapies and research investment are directed to the right, but consequences of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic show the extraordinary potential of left-sided interventions.

Figure 2.

Prevention and treatment of viral-induced exacerbations. The figure illustrates potential ways of mitigating the effects of respiratory viral infections on exacerbations of chronic obstructive pulmonary disease and asthma. Nonpharmaceutical interventions have been of proven efficacy in preventing transmission but may come at a significant societal cost. Novel methods to block viral adhesion and invasion of the mucosa have a high potential. Vaccination can provide effective immunity against severe infections, although it has so far proved difficult for important viral and bacterial pathogens. A range of drugs are already available for treating active viral infections, but strategies have yet to evolve for their early use.