The human respiratory tract is a highly efficient oxygenation system with a large surface area and surplus capacity (if all 600 million alveoli are stretched out, they can cover a tennis court). The alveoli, lined by thin flat cells, are exposed to inhaled air on one side and de-oxygenated blood in capillaries on the other.
This delicate system is exposed to inhaled noxious insults also – biological (bacterial, fungal, viral), chemical (smoke and particles) and allergy-inducing material (dust, pollen, animal fur), throughout life. As a consequence, many develop progressive lung damage and chronic lung disease – a very common non-communicable disease (NCD) with high morbidity and mortality ( approximately 30% of all NCD deaths).
The COVID-19 pandemic taught us the vital importance of the face mask in preventing coronavirus infection. The Hindu was a pioneer to promote universal mask use, and, after initial reluctance, many organisations world-wide adopted this measure. We describe the multiple benefits of face mask beyond the pandemic.
Effective intervention
Some inhaled viral respiratory infections such as influenza have high mortality at extremes of age; others, like the ‘common cold’ are an important cause for loss of person-hours and productivity. Universal mask-use is an effective preventive intervention against such diseases – it does not completely prevent viral entry, but drastically reduces the viral dose – low doses serve to stimulate immunity with lowered risk of overt disease.
With 7,00,00,000 tuberculosis (TB) cases annually, India is the TB capital of the world. TB is the commonest chronic respiratory infection, the most important infectious disease in India, with WHO-estimated annual 26,40,000 new cases, 4,36,000 deaths, 2.8% and 14% multi-drug-resistance in new and old cases, respectively ( 2019 data: https://tbfacts.org/tb-statistics-india/). TB bacilli, expelled by those with pulmonary TB while coughing or spitting are inhaled by others. Unlike viruses with short life-span in atmosphere, TB bacilli in sputum survive even in dried state, for days to weeks and get air-borne. If everyone wears a mask while outside home, spitting in public places and inhalation of TB bacilli will drastically come down.
These two benefits – prevented viral infections and TB – can translate into considerably reduced acute and chronic respiratory diseases, loss of lives and livelihoods.
India is also the diabetes capital of the world, with urban diabetes prevalence of over 10% in adults above age 40. Diabetes and TB are a deadly combination – each making the other worse – a vicious cycle that afflicts hundreds of thousands in India. Universal masking, continued beyond the pandemic, can minimise the risk of TB in diabetics.
Our metros suffer high levels of air pollution with toxic particulate matter, causing progressive irreversible impairment of lung function. In Delhi, air pollution became so bad that Supreme Court had to intervene to improve matters on a war footing. While non-polluting motor vehicles, avoiding crop burning etc. are public health measures to curtail air pollution, face mask offers considerable protection from inhaling toxic particles and to a lesser extent even noxious fumes.
Occupational hazard
Some occupations expose individuals to inhalation of particulate asbestos, carbon, silica etc. which also progressively impair lung function -- appropriate face masks are an important health imperative for them.
Smoking in public, although banned, continues to be a problem in India -- passive smoking puts even non-smokers at risk. Insistence on wearing a mask in public will be a deterrent to smoking and will protect smokers and non-smokers alike.
Respiratory allergies
As every physician knows, respiratory allergy – ‘allergic rhinitis’ and ‘extrinsic allergic asthma’, mostly due to inhaled ‘allergens’, are very common problems in children and adults, accounting for approximately 20% to 30% of all outpatient visits. Many with respiratory allergy, who consistently wore masks during the COVID-19 pandemic, have found considerable relief from chronic upper and lower respiratory symptoms and intend to continue using masks beyond the pandemic.
Hospitals, with their concentration of patients with acute and chronic respiratory infections, pose an important health risk to people working there – a hazard highlighted by loss of lives of many health-care workers during the current COVID-19 pandemic. However, the risk of other hospital-acquired respiratory diseases cannot be under-rated. Routine use of face masks will certainly reduce the risk to health-care professionals, and should be practised beyond the pandemic. Even those who visit hospitals for healthcare – patients and their bystanders, at increased risk of contracting respiratory infections – will be well-advised to routinely use face masks during hospital visits.
Indeed, the simple face mask, which ancient Jain Munis used and promoted, has multiple benefits well beyond the pandemic.
(Dr M .S. Seshadri, Former Professor of Medicine and Clinical Endocrinology, Christian Medical College, Vellore is currently Medical Director, Thirumalai Mission Hospital, Ranipet. Dr T. Jacob John is former Professor of Clinical Virology, Christian Medical College, Vellore, and former President of the Indian Academy of Pediatrics.)
