Hydrating the respiratory tract: An alternative explanation why masks lower severity of COVID-19

被引:34
作者
Courtney, Joseph M. [1 ]
Bax, Ad [1 ]
机构
[1] NIDDK, Lab Chem Phys, NIH, Bethesda, MD 20892 USA
关键词
HUMIDITY; TEMPERATURE; INFECTIONS;
D O I
10.1016/j.bpj.2021.02.002
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
The seasonality of respiratory diseases has been linked, among other factors, to low outdoor absolute humidity and low indoor relative humidity, which increase evaporation of water in the mucosal lining of the respiratory tract. We demonstrate that normal breathing results in an absorption-desorption cycle inside facemasks, in which supersaturated air is absorbed by the mask fibers during expiration, followed by evaporation during inspiration of dry environmental air. For double-layered cotton masks, which have considerable heat capacity, the temperature of inspired air rises above room temperature, and the effective increase in relative humidity can exceed 100%. We propose that the recently reported, disease-attenuating effect of generic facemasks is dominated by the strong humidity increase of inspired air. This elevated humidity promotes mucociliary clearance of pathogens from the lungs, both before and after an infection of the upper respiratory tract has occurred. Effective mucociliary clearance can delay and reduce infection of the lower respiratory tract, thus mitigating disease severity. This mode of action suggests that masks can benefit the wearer even after an infection in the upper respiratory tract has occurred, complementing the traditional function of masks to limit person-to-person disease transmission. This potential therapeutical use should be studied further.
引用
收藏
页码:994 / 1000
页数:7
相关论文
共 45 条
[1]   The mechanism of exercise-induced asthma is ... [J].
Anderson, SD ;
Daviskas, E .
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY, 2000, 106 (03) :453-459
[2]   Visualizing Speech-Generated Oral Fluid Droplets with Laser Light Scattering [J].
Anfinrud, Philip ;
Stadnytskyi, Valentyn ;
Bax, Christina E. ;
Bax, Adriaan .
NEW ENGLAND JOURNAL OF MEDICINE, 2020, 382 (21) :2061-2063
[3]  
[Anonymous], J AEROSOL MED PULM D
[4]   THE MOISTURE RELATIONS OF TEXTILE FIBRES AT HIGH HUMIDITIES [J].
ASHPOLE, DK .
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL AND PHYSICAL SCIENCES, 1952, 212 (1108) :112-123
[5]  
ASTM International, 2018, D1909132020E1 ASTM
[6]   Seasonality of Respiratory Viral Infections: Will COVID-19 Follow Suit? [J].
Audi, Amani ;
AlIbrahim, Malak ;
Kaddoura, Malak ;
Hijazi, Ghina ;
Yassine, Hadi M. ;
Zaraket, Hassan .
FRONTIERS IN PUBLIC HEALTH, 2020, 8
[7]  
Bafadhel M., 2020, STEROIDS COVID 19 ST
[8]   Exhaled particles and small airways [J].
Bake, B. ;
Larsson, P. ;
Ljungkvist, G. ;
Ljungstrom, E. ;
Olin, A-C .
RESPIRATORY RESEARCH, 2019, 20 (1)
[9]   Efficacy of a heat exchanger mask in cold exercise-induced asthma [J].
Beuther, David A. ;
Martin, Richard J. .
CHEST, 2006, 129 (05) :1188-1193
[10]  
Brosseau LM, 2020, NEW ENGL J MED, V383, P2092, DOI 10.1056/NEJMc2030886