A calcium-rich nasal spray reduces the number of small respiratory droplets exhaled among people at high risk for COVID-19.

www.eurekalert.org

Robust evidence indicates that SARS-CoV-2, the virus that causes COVID-19, spreads primarily via respiratory droplets in the exhaled air of infected persons. Although the wearing of face masks is a critical component of global public health strategies to prevent spread of the disease, small respiratory droplets that are less than 1 micron in diameter can pass through the masks. A recent study demonstrates that administration of a calcium-rich nasal spray may reduce the number of small respiratory droplets exhaled among people at high risk.

Components of the upper respiratory system – the nose, trachea, and bronchi – play critical roles in protecting the body from infection by capturing inhaled pathogens in mucus, which can then be swallowed and destroyed in the gut. If pathogens are not cleared in a timely manner, they can be transported deeper into the lungs or spread to others via exhaled air in droplets. Calcium binds with mucin (a sticky component of mucus), increasing the surface elasticity of the mucus-airway surface and helping to prevent the formation of small droplets.

The study involved three distinct high-risk groups of people: students, essential workers (food processing employees), and people in quarantine with an infected family member. In all, 92 people participated in the study. Each of the participants received a dose of nasal spray composed of calcium chloride and sodium chloride in distilled water (with a salt content similar to seawater), administered via a hand-held mister for one to two minutes. The authors of the study measured the participants' exhaled airborne particles before and after receiving the spray using a particle detector.

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They found that the number of small exhaled particles decreased by an average of 75 percent across the three different groups, markedly outperforming surgical masks. These findings suggest administration of a calcium-rich nasal spray can play an important role in reducing the spread of COVID-19. The authors posited that the spray could be used in both personal and public health settings with minimal or no contact.