Diseases of the respiratory system, from the ordinary cold to pneumonia with respiratory distress syndrome, septic shock, and multi-organ failure, are all included under the umbrella term COVID-19. Angiotensin-converting enzyme 2 (ACE2) is the cellular receptor for SARS-CoV-2, so ACE2- expressing cells can act as target cells and are susceptible to infection. The oral cavity has a high expression of ACE2 receptors, making it a potentially dangerous site for SARS-CoV-2 infection. Furthermore, the virus can be found in saliva even before COVID-19 symptoms manifest, placing asymptomatic/presymptomatic patients at a high risk of virus transmission. Many studies reported that a lower likelihood of transmission through salivary droplets or aerosols could result from decreasing oral virus load, which would help to manage the spread. 

The available data on the efficiency of oral antiseptics in reducing the transmission of coronaviruses in both in-vitro and in-vivo settings were addressed in this review paper. A total of 619 articles were found using the initial search method that combed through Medline (through PubMed) and Web of Sciences. The authors considered 17 articles that evaluated the virucidal efficacy of oral antiseptics against coronaviruses. 

There is sufficient in-vitro evidence to support the use of antiseptics to reduce the viral load of SARS-CoV-2 and other coronaviruses. The three most recommended oral antiseptics in the scientific works against SARS-CoV-2 have been PVP-I, H2O2, and CPC. It has been reported that the microbicidal activity of PVP-I shows a reduction of 72% in 30 min after its use as a rinse. The substantivity of CPC is high, from 3 to 5 h, enabling enhanced efficacy against the virus for a longer time. Adverse effects observed with long-term use of CPC were discoloration of the teeth and tongue and slight transient irritation of the gums, and aphthous ulcers in some individuals. H₂O₂ has several risks and limitations in its oral use. Povidone-iodine is safe in the nose for up to 1.25% and mouth for up to 5% for up to five and six months, respectively. Absorption of iodine is poorly described, inconsistently analyzed, and without clear conclusions. PVP-I has been demonstrated to be systemically risk-free at concentrations up to 5% daily for five months.

Source: Mateos-Moreno, M. V., Mira, A., Ausina-Márquez, V., & Ferrer, M. D. (2021). Oral antiseptics against coronavirus: in-vitro and clinical evidence. The Journal of hospital infection, 113, 30–43.