Mouthwash effective against Novel Coronavirus (COVID-19)
Ever since WHO declared SARS Cov-2 or the COVID-19 disease as pandemic, the healthcare fraternity is working continuously to find ways to tame the virus. Several attempts are being made worldwide. Among these, search for mouthwash that is effective against COVID-19 is trending too. Here are updates from few such studies that have reported the effectiveness of certain mouthwash/ topical formulations.
Povidine – Iodine Mouthwash – The wonder liquid against Coronavirus (COVID-19) ?
Respiratory hygiene measures such as throat sprays or gargling can be considered to reduce the risk of SARS-CoV-2 transmission via the oral and nasal mucosa. Australian Dental Association, US Centers for Disease Control and Prevention, Dental Council of India and Indian Dental Association has recommended using a pre-procedural mouthwash with Povidine- Iodine in their COVID-19-related guidelines.
In an in-vitro study conducted at Duke-NUS Medical School, Singapore, the researchers have found that Povidine- Iodine based products have shown virucidal activity against SARS-CoV-2. The study reports that Povidine- Iodine products like gargle and mouth wash (PVP-I 1%) and throat spray (PVP-I 0.45%) achieved ≥ 99.99% virucidal activity against SARS-CoV-2, corresponding to ≥ 4 log10 reduction of virus titre, within 30 s of contact.
A group of investigators from The Institute for Antiviral Research at Utah State University Logan, conducted an in-vitro study. They have reported that PVP‐I oral antiseptic preparations rapidly inactivated SARS‐CoV‐2 virus in vitro. The viricidal activity was present at the lowest concentration of 0.5 % PVP‐I and at the lowest contact time of 15 seconds.
Based on the available evidences, it can be justified to use Povidine Iodine mouthwash as an adjunct to personal protective equipment, for dental and surgical specialties to reduce the risk of COVID-19 infection.
The age old Samaritan – Chlorhexidine mouthwash against COVID -19 ?
A case report from Journal of Korean Medical Sciences published in May 2020 shows that Chlorhexidine mouthwash was effective in reducing the SARS Cov-2 viral load in saliva transiently for 2 hours. The concentration of Chlorhexidine gluconate used was 0.12%, 15mL for 30 seconds. However, this study has certain limitations. It was conducted among 2 patients and did not involve any comparison groups. Hence, results need to be interpreted cautiously.
Apart from the above mentioned report, there is other analyses showing evidences on Chlorhexidine at concentration of 0.05 % is effective against SARS CoV-2. It has to be noted that Chlorhexidine mouthwashes are usually available in 0.12 and 0.2% concentrations. Both of which are 2 to 4 times more concentrated than the 0.05% chlorhexidine solution shown to be effective against COVID-19.
Hydrogen Peroxide based mouthwash
The recommended oral rinse concentrations of Hydrogen Peroxide is 1.5% and 3.0%. It was minimally effective as a viricidal agent after contact times as long as 30 seconds. This was compared against efficacy of Povidine- iodine mouthwash and found to be inferior. However, Hydrogen Peroxide mouthwash could be alternative for Povidine- Iodine mouthwash despite the study results. Further researches can throw light on Hydrogen Peroxide mouthwashes against SARS CoV-2.
Ethanol/ Alcohol based mouthwash
Evidences from studies provide proof-of-concept that mouthwashes containing essential oils with 21%–27% ethanol can inactivate enveloped viruses, both in the lab and in humans. The likely mechanism is damage to the lipid envelope. Ethanol in combination with essential oils may provide a more effective formulation. Thus, these types of mouthwash may be effective against SARS-CoV-2, although studies have not been conducted. Although it seems possible theoretically, clinical studies are required.
Scope for Research
As healthcare fraternity relies on evidence based approaches there are several questions to be answered.
- Can mouthwash reduce the viral load in oral and oropharynx region?
- Clinical effectiveness of various available mouthwash ?
- Would a combination of agents in lower amounts be better tolerated, reducing adverse effects, and remain effective?
- What combinations or agents, contact time and frequency of use would induce virucidal activity and reduce infectivity of SARS-CoV-2?
With the available evidences till date, use of Povidine- Iodine mouthwash can be useful in dental practices. It can reduce the viral load if present and reduce the risk of transmission of virus due to dental procedures. Alternatively, Chlorhexidine mouthwashes can also be used.
Clinical studies with robust design and appropriate power are needed. Determination of the most effective composition should be the focus. Self-reported, non-randomized, unblinded studies are not reliable and need to be avoided.