It is well known now that the nasal mucosa represents a vulnerable area for coronavirus to colonize for its abundant blood vessels, mucinous glands and serous glands which create a humid environment. As reported earlier, angiotensin converting enzyme-2 (ACE2) expression was found in the basal layer of the nonkeratinizing squamous epithelium in nasal mucosa, indicating that coronavirus may infect nasal mucosa cells if basal layer is exposed due to nasal mucosa barrier breakdown.1 It has been seen that human coronavirus causes disruption of the ciliated epithelium and ciliary dyskinesia which can impair mucociliary clearance. Damage to the respiratory epithelium, due to coronavirus infection, may occur without overt clinical symptoms.2 Therefore, it is mandatory to pay attention to the protection of upper respiratory tract and mucosa.
Nasal rinsing is often recommended as an additional non-pharmacological preventive strategy to clean the nasal cavities by removing antigens, inflammatory mediators, and microorganisms such as bacteria and viruses; in particular, nasal rinsing can reduce the viral load in the nasal cavities. The data supporting nasal rinsing for coronaviruses may not be aplenty, but there are few studies on the use of saline nasal irrigation as preventive strategy of upper respiratory tract infections (URTIs).
For e.g., Slapak et al.3 showed that the use of nasal rinsing three times daily for 8 weeks, reduced URTI episodes more than the control group without treatment, with a consistent improvement in symptoms, medication consumption, reported illness, school absence, and complication rate. Similarly, Tano and Tano4 suggested that a daily nasal spray with saline can prevent nasal symptoms of common cold in a population of otherwise healthy adults.
Recently, Ramalingam et al.5 conducted a pilot, randomized controlled trial of nasal rinsing and gargling versus standard care, in healthy adults within 48 hours of URTI onset to assess recruitment, acceptability, symptom duration, and viral shedding of a large number of viruses such as rhinovirus, enterovirus, influenza A virus, and coronavirus. At the end of the study, the authors showed that in the intervention arm, duration of illness was lower by 1.9 days, over-the-counter medications use by 36%, transmission within household contacts by 35% and viral shedding by ⩾0.5 log10/day. When individuals infected with similar viruses (rhinovirus, coronavirus, enterovirus, and influenza virus) were compared, 30% more individuals had reduction in viral shedding by ⩾0.5 log10 per day in the intervention arm.
Studies have thus indicated that nasal rinsing plays a defensing role in improving the innate antiviral immunity of the nasal mucosa cells, for e.g., another study suggested that epithelial, fibroblast, and hepatic cells have enhanced antiviral activity in the presence of increasing concentrations of sodium chloride even in the case of infection with a coronavirus.6.
Nasal rinsing is inexpensive and can be performed at home. It is rarely accompanied by adverse effects, although the use of hypertonic solutions can lead to the irritation of nasal mucosa and a greater sensation of burning in some cases.7 It is also known to cure sinusitis and migraine related symptoms that are commonly associated with with the common cold.
- Yan Y, Chen H, Chen L, et al. Consensus of Chinese experts on protection of skin and mucous membrane barrier for health-care workers fighting against coronavirus disease 2019. Dermatol Ther. 2020; DOI: 10.1111/dth.13310.
- Chilvers MA, McKean M, Rutman A, et al. The effects of coronavirus on human nasal ciliated respiratory epithelium. Eur Resp J 2001;18(6):965–70.
- Slapak I, Skoupá J, Strnad P, et al. Efficacy of isotonic nasal wash (seawater) in the treatment and prevention of rhinitis in children. Arch of Otolaryngol–Head & Neck Surg 2008;134(1):67–74.
- Tano L, Tano K. A daily nasal spray with saline prevents symptoms of rhinitis. Acta Oto-Laryngologica 2004;124(9):1059–62.
- Ramalingam S, Graham C, Dove J, et al. A pilot, open labelled, randomised controlled trial of hypertonic saline nasal irrigation and gargling for the common cold. Scientific Reports 2019;9(1):1015.
- Ramalingam S, Cai B, Wong J, et al. Antiviral innate immune response in non-myeloid cells is augmented by chloride ions via an increase in intracellular hypochlorous acid levels. Sci. Rep 2018;8(1):13630.
- Casale M, Moffa A, Cassano M, et al. Saline nasal irrigations for chronic rhinosinusitis: From everyday practice to evidence-based medicine. An update. Int J Immunopath and Pharmacol2018;32:2058738418802676.
UIN: 81HP30R