Regular gargling with an antiseptic such as 1% povidone iodine (PVP-I) may be helpful in SARS-CoV-2 viral clearance in stage 1 COVID-19 patients who are asymptomatic or have mild symptoms for the first two days of the infection, suggests a preliminary study from Malaysia posted on the preprint server medRxiv.¹ 

A randomized trial with an open label design was carried out in a tertiary hospital in Malaysia to investigate the effectiveness of regular gargling in eliminating the SARS-CoV-2 in the throat and nasopharynx in 20 patients with confirmed Stage 1 Covid-19. The effects of thrice-daily gargling using 1% PVP-I, essential oils and tap water for 30 seconds was compared. All the three study arms of the trial including the control group had five subjects each. Nasopharyngeal and oropharyngeal swabs were collected at day 4, 6 and 12 prior to the early morning gargle. Gargling with PVP-I resulted in 100% viral clearance within 4 days of the intervention and no virus was detected on Day 6 and Day 12 in any of the five patients. After gargling with essential oils, there was one positive sample in all the specimens collected, whereas in the tap water group, two samples were negative, while three tested either positive or were inconclusive on Day 4, Day 6 and Day 12. There were no side effects in any group.

This study has shown that gargling with PVP-I resulted in 100% viral clearance in Stage 1 Covid-19 patients, gargling with essential oils achieved 80% viral clearance, tap water led to 20% viral clearance at day 6, while in the control group, without any intervention, the viral clearance on the sixth day was 0%.¹ 

COVID-19 is a droplet or airborne infection and throat is a major reservoir for SARS-CoV-2. In a Nature study, the pharyngeal shedding of the virus was very high in the first week from onset of symptoms and peak shedding occurred on the fourth day when the symptoms were mild in nature and mirrored that of an upper respiratory tract infection. ² A study from the University of Hong Kong, published in December last year, has shown that Omicron, the latest SARS-CoV-2 variant of concern, which triggered the third wave in the country, replicated more rapidly in the human bronchus compared to the delta variant and the ancestral strain. The rate of multiplication was 70 times higher 24 hours after the infection. But it multiplied slowly in the human lung tissue, more than 10 times lower, than the wild-type SARS-CoV-2 virus. ³ These observations favor an efficient human to human transmission making stage I patients as potential source of COVID-19, who can spread the virus to their close contacts and also others in their vicinity. “It is therefore imperative to reduce the viral load in oropharynx with adequate oral prophylactic measures,” write Pattanshetty et al in the journal Oral Diseases. ⁴ 

Among the available antiseptics, PVP‐I has the broadest spectrum of antimicrobial activity covering Gram-positive and Gram-negative bacteria, viruses (both enveloped and nonenveloped), fungi, protozoa and bacterial spores and has low resistance potential.^5,6 The wider virucidal spectrum of PVP-I is particularly relevant in view of the ongoing COVID-19 pandemic. The present study makes the case for PVP-I to be part of the treatment and management of Stage 1 COVID-19 patients. 

While hand washing, masking (double masking with 3-layered masks), physical distancing, avoiding public places and poorly ventilated closed indoor spaces and self-isolation for positive cases are the usually recommended protective measures, inclusion of gargling with an antiseptic such as PVP-I will add to the protective measures recommended for people at risk of infection and to COVID-19 positive patients. 

References 

1. Mohamed NA, et al. Early viral clearance among covid-19 patients when gargling with povidone-iodine and essential oils – a clinical trial. MedRxiv. September 9, 2020. doi: https://doi.org/10.1101/2020.09.07.20180448.
2. Wölfel R, et al. Virological assessment of hospitalized patients with COVID-2019. Nature. 2020 May;581(7809):465-469.
3. https://www.med.hku.hk/en/news/press/20211215-omicron-sars-cov-2-infection, dated 15 December, 2021.
4. Pattanshetty S, et al. Povidone-iodine gargle as a prophylactic intervention to interrupt the transmission of SARS-CoV-2. Oral Dis. 2020;10.1111/odi.13378.
5. Kanagalingam J, et al. Practical use of povidone-iodine antiseptic in the maintenance of oral health and in the prevention and treatment of common oropharyngeal infections. Int J Clin Pract. 2015;69(11):1247-56.
6. Kawana R, et al. Inactivation of human viruses by povidone-iodine in comparison with other antiseptics. Dermatology. 1997;195 Suppl 2:29-35. doi: 10.1159/000246027.