Condition category
Infections and Infestations
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
COVID-19 is a condition caused by the coronavirus (called SARS-CoV-2) that was first identified in late 2019. This virus can infect the respiratory (breathing) system. Some people do not have symptoms but can carry the virus and pass it on to others. People who have developed the condition may develop a fever and/or a continuous cough among other symptoms. This can develop into pneumonia. Pneumonia is a chest infection where the small air pockets of the lungs, called alveoli, fill with liquid and make it more difficult to breathe.
In 2020, the virus has spread to many countries around the world and neither a vaccine against the virus or specific treatment for COVID-19 has yet been developed. As of March 2020, it is advised that people minimize travel and social contact, and regularly wash their hands to reduce the spread of the virus.
Groups who are at a higher risk from infection with the virus, and therefore of developing COVID-19, include people aged over 70 years, people who have long-term health conditions (such as asthma or diabetes), people who have a weakened immune system and people who are pregnant. People in these groups, and people who might come into contact with them, can reduce this risk by following the up-to-date advice to reduce the spread of the virus.
Some over-the-counter mouthwash solutions have been shown to kill bacteria and viruses in laboratory studies. This study aims to test this effect in people with COVID-19.

Who can participate?
Patients aged 18 and older who have tested positive for COVID-19

What does the study involve?
Participants will be randomly allocated to receive a strong mouthwash solution, to be used 3 times a day for 2 weeks, or treatment as usual.

What are the possible benefits and risks of participating?
Possible benefits include faster recovery and fewer secondary bacterial infections in the upper respiratory tract. Possible risks include mouth irritation, especially if there are mouth ulcers or sensitivity to the components, as well as digestive system irritation if hydrogen peroxide is ingested in quantities larger than the total daily recommended dose.

Where is the study run from?
1. Hazm Mebaireek General Hospital (Qatar)
2. Communicable Disease Center - Hamad Medical Corporation (Qatar)

When is the study starting and how long is it expected to run for?
April 2020 to November 2020

Who is funding the study?
Hamad Medical Corporation (Qatar)

Who is the main contact?
Dr Khalid Mukhtar

Trial website

Contact information



Primary contact

Dr Khalid Mukhtar


Contact details

Medical Research Center
Hamad Medical City
Doha Industrial Area (west)
+974 (0)77446394

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number

MRC 05-106

Study information

Scientific title

Effect of regular use of hydrogen peroxide and chlorhexidine gluconate mixed solution for mouth wash and gargles on the COVID-19 recovery rate: a randomized controlled trial


Study hypothesis

The development and progression of the disease following exposure to SARS-CoV-2 is affected by the microbial communities in the oral cavity; proposing a "complicit agent" hypothesis, either a single microbial agent effect (presence of complicit or absence of a protective) or the state of dysbiosis in general. Meanwhile, game theory and evolutionary biology suggests that inhibiting cooperation - reciprocal altruism - between two organisms can negatively affect their survival. The researchers propose that regular use of potent mouthwash can improve the disease course, as the strain of the continual reduction in the microbial load is likely to inhibit their cooperation.

Ethics approval

Approved 20/08/2020, Hamad Medical Corporations' Medical Research Center IRB (Medical Research Center, Hamad Medical City, Doha, Qatar; +974 (0)5554 6316;, ref: MRC 05-106

Study design

Interventional randomized parallel trial

Primary study design


Secondary study design

Randomised parallel trial

Trial setting


Trial type


Patient information sheet

No participant information sheet available


COVID-19 (SARS-CoV-2 infection)


New admissions (24 hrs) will be screened for eligibility. Recruited subjects will be randomly allocated to either the study or control group.

Study group: Potent disinfectant solution (10 ml Chlorhexidine gluconate 0.2% + 5 ml of hydrogen peroxide 6%) will be provided three times daily for 2 weeks, to be used for mouth rinse and gargles (>30 sec) and to avoid eating or drinking for at least 5 more minutes

Control group: treatment as usual

Intervention type



Drug names

Primary outcome measure

1. Recovery assessed using clinical improvement along with a negative COVID RT-PCR test at 5 and 15 days of starting treatment
2. Changes in the CT-values of COVID-19 RT-PCR inconclusive test at 5 and 15 days of starting treatment

Secondary outcome measures

1. Clinical symptoms assessed using the Sore Throat Assessment Tool for the first 5 days
2. COVID progression (ICU intubation vs discharge or transfer to quarantine) recorded by reviewing medical records within the study duration
3. Hospital stay measured using (days) at discharge; or at the end of study for those remained admitted
4. Disposition type (discharged/death) measured using hospital records entries at the time of discharge, or reported mortality during hospital stay

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Age 18 years and older
2. COVID-19 reported via positive PCR within 2 weeks of admission
3. Conscious, oriented and can comprehend the study purpose and risks

Participant type


Age group




Target number of participants


Total final enrolment


Participant exclusion criteria

1. Pregnancy (females)
2. Intubated (at the time of recruitment) or had any reported cognitive impairment that can prevent proper comprehension of the study or communicating side effects
3. Contra-indication for mouth wash use, e.g. reported allergies to the solution constituents, recent facial/head injuries, maxillofacial conditions

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Hazm Mebaireek General Hospital
Hamad Medical Corporation Doha Industrial Area (west)

Trial participating centre

Communicable Disease Center - Hamad Medical Corporation
Hamad Medical City

Sponsor information


Hamad Medical Corporation

Sponsor details

Medical Research Center
Hamad Medical City
+974 (0)40256410

Sponsor type




Funder type


Funder name

Hamad Medical Corporation

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Planned publication in a high-impact peer-reviewed journal.

IPD sharing statement
The data sharing plans for the current study are unknown and will be made available at a later date.

Intention to publish date


Participant level data

To be made available at a later date

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

05/10/2020: Trial's existence confirmed by Hamad Medical Corporations' Medical Research Center IRB.