Systematic Review

Cystic Fibrosis in the SARS-CoV-2/COVID-19 Pandemic

Hannah R. Mathew; May Y. Choi; Michael D. Parkins; Marvin J. Fritzler

Disclosures

BMC Pulm Med. 2021;21(173) 

In This Article

Abstract and Introduction

Abstract

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the development of life-threatening COVID-19 are believed to disproportionately affect certain at-risk populations. However, it is not clear whether individuals with cystic fibrosis (CF) are at a higher risk of COVID-19 or its adverse consequences. Recurrent respiratory viral infections are often associated with perturbation and pulmonary exacerbations of CF as evidenced by the significant morbidity observed in CF individuals during the 2009 H1N1 pandemic. The primary goal of this review was to systematically survey published accounts of COVID-19 in CF and determine if individuals with CF are disproportionally affected by SARS-CoV-2 and development of COVID-19.

Methods: We conducted a systematic literature search using EMBASE and Medline between April 28 and December 10, 2020. Six evaluable studies reporting on a total of 339 individuals with CF who developed COVID-19 were included in this study.

Results: We found that although individuals with CF generally experience acute exacerbations of lung disease from infectious agents, COVID-19 incidence estimates in CF appear to be lower than in the general population. However, there are reports of subsets of CF, such as those who had organ transplants, that may experience a more severe COVID-19 course. Potential protective mechanisms in the CF population include pre-pandemic social isolation practices, infection prevention and control knowledge, altered expression of angiotensin-converting enzyme, and the use of certain medications.

Conclusions: Although individuals with CF are at risk of acute exacerbations often precipitated by respiratory tract viral infections, published evidence to date indicated that individuals with CF do not experience higher risks of contracting SARS-CoV-2 infection. However, there is evidence that some subsets within the CF population, including those post-transplantation, may experience a more severe clinical course. As SARS-CoV-2 variants are identified and the pandemic goes through additional waves of disease outbreaks, ongoing monitoring of the risk of COVID-19 in individuals with CF is required.

Introduction

Cystic fibrosis (CF) is a classic Mendelian autosomal recessive disorder and is the most common fatal genetic disease in North America.[1] The predominant incidence estimate of the disorder is 1/2500 live births in Caucasians, with a mean prevalence of 0.797/10,000 in the United States of America.[2,3] The estimated median age of survival, which denotes the estimated age that 50% of infants born in a given year will live beyond, reaches 50 years and beyond in some countries.[4] CF has been traced to the inheritance of two abnormal copies of the CF transmembrane conductance regulator (CFTR) gene.[1] Abnormal CFTR are associated with aberrant salt and water transport across epithelial surfaces. Within the lungs, this manifests with mucus accumulation and the inability to clear inhaled organisms, giving rise to chronic infection and inflammation leading to airway remodelling and disease.[1] CFTR is also involved in the movement of bicarbonate; defects in its function lowers the pH of the airway surface liquid.[1,5] Studies have shown this pH alteration in animal models impairs innate immunity by inhibiting the function of antimicrobial peptides.[1,6,7] Data also suggests that CFTR gene variants cause epithelial cells to inherently respond in an increasingly pro-inflammatory manner.[1]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the development of life-threatening COVID-19 are believed to disproportionately affect certain at-risk populations such as those over the age of 50 as well as those with diabetes, hypertension, cardiovascular diseases, and chronic respiratory disease.[8–11] However, it is not clear whether individuals with CF are at a higher risk of COVID-19 or its adverse consequences. This topic has been of great concern due to the importance of recurrent respiratory viral infections in disease perturbation and pulmonary exacerbations.[12–14] Additionally, significant morbidity was observed in individuals with CF during the 2009 H1N1 pandemic.[15,16] The primary goal of this study was to survey published accounts of COVID-19 in CF and determine if CF constitutes an 'at risk' population with respect to morbidity or mortality from COVID-19.

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