• Oronasal saline irrigation is an inexpensive intervention to prevent and relieve common colds and upper respiratory infections.
• COVID-19 patients may also benefit, as saline irrigation of the nose and throat was found to reduce nasopharyngeal viral load, fasten viral clearance, and relieve symptoms of COVID-19.
• Overall, the small studies point to a potential benefit of saline irrigation on transmission, hospitalization, oxygen need, ICU admission, and/or mortality; confirmation in large trials is warranted.
• Mechanisms of saline include, apart from the rinse effect that can limit micro-aspiration of virus and secretions from the nasopharynx to deeper airways and lungs, also direct effects of iso- or mild hypertonic saline on SARS-CoV-2 replication (impairment of growth and fusion in vitro), mucosal hydration, mucociliary clearance, ENaC channel activity, and obstructive mucus/NET formation, all mechanisms that can help to reduce and prevent the development of more invasive severe disease.
• Oral and nasal saline rinsing can be considered for prevention and as an early intervention in SARS-CoV-2 infection, adjunctive to current standard protection including mask wear, distancing, and hand hygiene.
• Saline nebulization can be considered in patients who cannot do saline irrigation, or with lower respiratory tract signs or symptoms: The released bioaerosol does not contain live virus.
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