Practical use of povidone-iodine antiseptic in the maintenance of oral health and in the prevention and treatment of common oropharyngeal infections

Kanagalingam, J.; Feliciano, R.; Hah, J. H.; Labib, H.; Le, T. A.; Lin, J.-C.

Upper respiratory tract infections (URTIs) are one of the most common reasons for presentation to primary practice by adults and children, and are a major cause of mild morbidity (56) . Symptoms range from the common cold, cough, pharyngitis and fever to occasionally more serious complications, and are associated with high societal costs due to loss in productivity, absenteeism from school and medical resources (57) . Most URTIs are caused by viruses, such as adenovirus, rhinovirus, influenza, coxsackievirus, herpes simplex virus, coronavirus and respiratory simplex virus (58) . However, current practices do not often consider the aetiological basis of the URTI, leading to inappropriate antibiotic prescription for URTI that are of viral origin (59) . This is particularly evident in the treatment of pharyngitis or sore throat, where only 5-30% of cases are because of bacterial infections (60) . Inappropriate and overuse of antibiotics further reinforce the importance of identifying alternative anti-infective agents (61) to complement physical and barrier interventions e.g. handwashing and wearing of masks to prevent and interrupt the spread of respiratory pathogens. The first step in the development of URTIs is the adherence and colonisation of the respiratory pathogen to the oropharyngeal mucosa. Assuming oral entry of such pathogens, gargling offers a practical measure for their eradication (62) . Gargling has been strongly advocated for both prevention and treatment of URTIs in Japan, a practice supported by findings from studies that looked at the role of gargling in both healthy individuals and those with frequent or persistent respiratory infections (62) (63) (64) . In these studies, gargling with either water or PVP-I (four times daily), respectively, were found to reduce the incidence of URTIs. Furthermore, in patients experiencing chronic respiratory infections, PVP-I was found to reduce the episodes of infections with P. aeruginosa, S. aureus (including MRSA) and H. influenzae by half (62) . These findings were further corroborated by a non-randomised study in which gargling with diluted PVP-I reduced the incidence of influenza-like illnesses or the common cold and subsequent absenteeism from school and the work place (65) . While the mechanism of gargling in the prevention of respiratory infections requires further investigation, an early study suggests that gargling may lead to the removal of oral/pharyngeal house dust mite protease which has been shown to increase infectivity of the influenza virus (64, 66) . Gargling, intensified by the presence of PVP-I, may therefore play an important role in the prevention or reduction in the incidence of infection through droplet transmission.