Use of oral antiseptics for SARS-CoV-2 infection

Dear Editor,

The health crisis triggered by the SARS-CoV-2 (COVID-19) pandemic and its rapid onset have placed humanity in combat with a pathogen that cannot be won at this moment with any pharmacological treatment that boasts sufficient scientific evidence.¹ While awaiting the results of ongoing clinical trials with different therapeutic options and looking forward to a vaccine that allows population immunity to be achieved, intermediate, fast, safe and verifiable solutions are necessary with limited research effort. A recent study reports that patients affected by COVID-19 have a high viral load in the oropharynx, especially during the first week after the onset of symptoms, which would partly explain its high transmission rate, its contagiousness and its rapid geographical spread.²

It is also known that different antiseptics (povidone iodine) have virucidal action on skin and mucosa, and are well tolerated for short-term treatments.³ In 2015, a study reported that the in vitro application of antiseptic products with povidone iodine achieved a decrease in the titres of the MVA (Modified Vaccinia Ankara) and MERS-CoV (Middle East Respiratory Syndrome) viruses, corresponding to a viral inactivation greater than 99% after 30 and 15 s of applying the mouthwash product (1% concentration) in MVA and MERS-CoV, respectively.⁴ These investigations were later expanded and with similar results both in the case of bacteria (Klebsiella pneumoniae Y Streptococcus pneumoniae) and with other viruses (SARS-CoV, influenza A-H1N1 and rotavirus). These findings are summarised in another publication in August 2019, prior to the epidemic situation.⁵

It would be feasible to hypothesise that treatment with mouthwashes/gargling with antiseptics (povidone iodine or others) could contribute to reducing the viral load of COVID-19 in sick patients, as well as reducing contagiousness through respiratory droplets towards other persons and the environment.⁴ This hypothesis could be tested quite simply and quickly by applying the scientific method with a study designed with paired data (cross-over or within patient), which would require a smaller number of patients. The viral load would be assessed before and after (at different times) the application of the oral antiseptic. Relevant questions to be resolved would be: an estimation of the minimum concentration necessary for the product to obtain positive results while minimising adverse effects; and determining the time during which the viral load in the oropharynx is low enough to have a protective effect for the patient, for others and for the environment. Likewise, it would be of interest to assess whether the decrease in the viral load in the oropharynx could have a clinically relevant effect in patients.

It should be noted that the studies cited above^4,5 were sponsored by a specific manufacturer of povidone iodine, therefore future studies should ensure the independence of the research groups to avoid conflicts of interest. The proposition of other possible prophylactic/therapeutic options would also be of importance, especially as an alternative to those subjects with COVID-19 infection in which povidone iodine presents some contraindication or precaution (pregnant women, children, goiter or hyperthyroidism), as stated in the product's technical data sheet: <https://cima.aemps.es/cima/dochtml/ft/36339/FT_36339.html>.

If positive results are obtained, this therapeutic option could be a practical and safe solution, pending more effective therapies or an adequate vaccine. It could be indicated for relatively short periods (1−2 weeks), coinciding with the greatest contagious wave. The application by the patient (in home isolation or during a hospital stay) would be simple to learn and to carry out. Additionally, antiseptics are easily accessible and are low cost, so this alternative could be feasible for countries with low economic resources.

This proposal has been sent to Spain’s Ministry of Health on behalf of the Drug Use Working Group of the Spanish Society of Family and Community Medicine (semFYC). Family practitioners are on the front line caring for patients with COVID-19 and trying to manage the elevated level of uncertainty in general and especially regarding the use of current drugs, that are all ‘off-label’ and lack the ‘backing’ of scientific evidence.¹ Possible solutions such as the one proposed, if its effectiveness is confirmed, even though modest, would contribute to improving the management of SARS-CoV-2 infection in both primary care and hospitals. In the current situation of health crisis, any step forward is a great step forward.