key: cord-0987871-9u6laxmp
authors: Steinmeyer, Reinhard
title: Open questions about povidone‐iodine based preventive measures. Comment to Martínez Lamas et al
date: 2020-08-04
journal: Oral Dis
DOI: 10.1111/odi.13589
sha: a7266d346c947aee7460b3331b16b9f22ef1c57a
doc_id: 987871
cord_uid: 9u6laxmp

nan

This article is protected by copyright. All rights reserved al. 2020), salivary viral load showed no evident trend of reduction five minutes after a rinse with 15 mL of 1% PVP-I for 1 min (Martínez Lamas et al. 2020 ). This is even more surprising since the simple procedure of gargling and spitting out may reduce viral load (Cimolai 2020) , at least for a short time. If the maximal reduction of salivary viral load occurs after two or three hours, this would have unfavourable consequences for the use of PVP-I in dental practice. However, one may ask whether the viral load detected in saliva 5 min after PVP-I rinse was alive and potentially infectious, or simply RNA from inactivated SARS-CoV-2? It would be important to repeat these experiments employing virus culture from saliva in order to examine potential infectivity.

Second, it is surprising that the effect of PVP-I persists so long (> 3 hours). One may suppose that viral load will recover quickly after rinsing, since new saliva is produced and viral shedding from infected mucosa and possibly salivary glands goes on. The role of salivary glands as a potential source of viral shedding is still debated (Da Silva Pedrosa 2020). Thus it would be important to examine the underlying mechanisms for the apparent long-lasting effectiveness of PVP-I, especially since water-soluble PVP-I has a short contact time with the oropharyngeal mucosa (for nasal mucosa: see Liang et al. 2020 ) and no 'depot effect' by long-lasting adhesion to mucosal surfaces like chlorhexidine or carrageenan.

Third, since the nasal epithelium is supposed to be the primary port of entry for the virus in most cases, administration of PVP-I into the nose is considered as local chemoprophylaxis and subject of a few registered trials. It would be helpful to repeat experiments like those of Martinez Lamas et al. in the nasal tract, i.e. to measure the viral load in nasal swabs at different times following nasal administration of PVP-I, but not only by PCR but also by virus culture to be able to detect infectious virus. This may help to optimize the timing of nasal PVP-I administration in relation to potential risky exposures and the method of application (e.g. nose drops, spray, nasal douche). Moreover, it was hypothesized that administration of local antiseptics into the nasal tract may be helpful in the early treatment of infected individuals in order to reduce local viral load and prevent the expansion of the nasal/nasopharyngeal infection downward in the airways (Liang et al. 2020) , thereby reducing viral spread into the lungs and risk of pneumonia.

Povidone-Iodine Demonstrates Rapid In Vitro Virucidal Activity Against SARS-CoV-2, The Virus Causing COVID-19 Disease

Efficacy of Povidone-Iodine to Reduce Viral Load

Are salivary glands the key players in spreading COVID-19 asymptomatic infection

In-Vivo Toxicity Studies and In-Vitro Inactivation of SARS-CoV-2 by Povidone-iodine In-situ Gel Forming Formulations

Is povidone-iodine mouthwash effective against SARS-CoV-2? First in vivo tests

Transmission routes of 2019-nCoV and controls in dental practice

This article is protected by copyright. All rights reserved