Hydrogen peroxidation occurs within a minute. The virus, therefore, has little chance of infecting an individual, as it requires at least 24 to 48 hours to attach to the mucous membrane and to penetrate to cause infection, the incubation period varying 2-14 days. [25,26]
A window of opportunity of at least 24 hours is therefore offered to inactivate the virus soon after entering either the oral or nasal cavities. Within a minute of that period and with concentrations of hydrogen peroxide as low as 1% and 0.5%, the virus is inactivated
as suggested in a recent study. 
Even when a more transmissible variant or sub-variant of the virus enters the oronasal cavities, there is sufficient time for hydrogen peroxide deactivation to happen, if it is used daily
. It must be noted, however, that the virus could escape residence in the oral and nasal cavities and their pharyngeal spaces to directly affect other parts of the trachea-bronchial tree including the alveolar pneumocytes, causing early disease with dire consequences. 
This is why the recommendation for early intervention with hydrogen peroxide nebulization is vital in such cases to inactivate the virus before it causes disease directly involving the alveoli. This subject has been extensively dealt with. [28-30]
For that reason, those at greater risk of direct invasion of the lungs with viruses such as healthcare workers, athletes, and those with lifestyle activities requiring hyperventilation, must also boost their immune system with adequate levels of micronutrients such as Vitamin C, D and E, folic acid, zinc, and magnesium
Other Rationale for Hydrogen Peroxide use in the Oronasal, and Oropharyngeal Cavities
The rationale for topical use of hydrogen peroxide in the oral cavity is that the mucosa of the oral cavity and the oropharynx has a robust epithelium that is not easily corroded. The stratified squamous keratinized and non-keratinized epithelial nature of the oral cavity and the oropharynx help to prevent damage. Noting that the reactive oxygen species generated by hydrogen peroxide has mutagenic properties, the epithelium of the oropharyngeal mucosae is even keratinized in some parts, 
making those areas less vulnerable to mutagenicity.
The nasal cavity and its postnasal space, on the other hand, present a challenge: the mucosa here is less robust, except in the nasal vestibule which has stratified squamous keratinized epithelium. The mucosal lining of the main nasal cavity as well as the nasopharynx is pseudo-stratified columnar type of epithelium interspersed with mucus secreting goblet cells 
, except in its roof including the adjacent surfaces of the superior conchae where olfactory epithelium exits. To limit corrosion of these less robust types of epithelia in the nasal cavity, a lower concentration of hydrogen peroxide (0.5%) has been recommended
. [18,33] That is the reason why only 2-3 drops of the 0.5% hydrogen solution per day are required and for a period of one minute.
Mutagenicity of Hydrogen Peroxide and other Adverse Effects
We have referred to this already but must address it more fully, as it is of the utmost importance in any recommendation of hydrogen peroxide topical use. In a publication in the British Medical Journal, we addressed that challenge 
, drawing attention to an extensive review on the subject by Walsh 
and Marshall et.al. 
So far, no evidence has been found in human studies of cellular mutation in oral use of hydrogen peroxide at concentrations of 3%. Even hydrogen peroxide use at concentrations of 6% for whitening of teeth has not shown any evidence of mutagenicity. In their review of hydrogen peroxide safety, it was noted that some individuals had used hydrogen peroxide daily for 6 years without deleterious effects. 
It is also to be noted that hydrogen peroxide is an essential product in the metabolism of innate immune cells to destroy pathogens through peroxidation. The ROS released in that process are quickly detoxified to protect body cells by enzymes such as catalase, superoxide dismutase, and glutathione peroxidase. 
Saliva has been found to contain peroxidase, catalase and glutathione reductase. 
Any excess of hydrogen peroxide in the oral cavity and oropharynx would therefore be detoxified by these enzymes in saliva.
Accidental swallowing of 3% hydrogen peroxide, however, is known to cause gastric irritation in some individuals.
In the two-year period of study of hydrogen peroxide use to prevent COVID-19, our attention has not been drawn to any such deleterious effect in those using the hydrogen peroxide solution.
Prophylactic Use of Oral Antiseptics in Dental Practice to Protect Patients and Staff from COVID-19
Recent data on the use of hydrogen peroxide in dental clinics suggests that it is useful in reducing SARS-CoV-2 viral load 
, corroborating the use of oral antiseptics employed in dental practice as an antidote to SARS-CoV-2 transmission
In the US especially, hydrogen peroxide prophylaxis in dental surgery has been adopted by the American Dental Association. 
In New Zealand, hydrogen peroxide use as prophylaxis has also been approved. 
In Ghana, both povidone and hydrogen peroxide are in use clinically for patients before non-surgical and surgical dental procedures (Personal communication - Dr. Mary Ayettey-Adamafio, co-author). This practice is intended to protect both patients and staff from contracting the coronavirus. It is helpful too for the patient, as the oral antiseptic inactivates other microbial organisms that might otherwise escape into the blood stream to cause disease. 
Clinical Use of Hydrogen Peroxide to Protect Healthcare Workers and Patients
This is the crux of our current research published to date. [17,18]
From our observations that very low concentrations of hydrogen peroxide protect hospital staff who are most at risk of contracting COVID-19, from the strong anecdotal evidence of hydrogen peroxide protection from the disease, and from the growing international interest in the use of oral antiseptics to prevent the disease, we recognize a providential guidance in March 2020 to investigate the relationship between hydrogen peroxide and coronaviruses. Indeed, since then, other investigators have also shared anecdotal evidence of hydrogen peroxide benefits even in treatment of COVID-19. [28,30]
While preparing a protocol for clinical investigation of the efficacy of hydrogen peroxide protection against COVID-19, we were fortuitously presented with an opportunity to observe eight emergency care nurses at the Shai-Osudoku District Hospital who, on their own volition, had been using hydrogen peroxide since May 2020 to protect themselves from the disease. At that time, the only preventive protocols were the established public health measures including mouth and nose covers, frequent washing of hands with soap under running water, and use of hand sanitizers. Only those who were managing confirmed COVID-19 cases wore the full personal protective equipment clothing suit. These emergency-care nurses wore ordinary scrubs; there were no vaccines available at the time; neither were there fail-proof therapeutic remedies for the disease.
Unknown to us, these eight healthcare workers had heard about our advocacy for 1% hydrogen peroxide daily use for mouth-washing and throat-gargling for one minute and 0.5% for nasal cleansing through several social platforms to save lives, and were using it. The reason for promoting hydrogen peroxide use was that team members and their relatives using the solution and who had been exposed to the disease had been protected. By May 2020, anecdotal evidence of hydrogen peroxide protection against COVID-19 had already become strong. Faced with the real challenge of rapid spreading of the disease, and without fail-proof preventive measures and therapeutic interventions, we were obliged to share more widely the anecdotal evidence of hydrogen peroxide protection with the wider family, friends, colleagues, neighbors and others including religious bodies, recognizing also that this antiseptic is an off-the-counter solution that had been in use in dental practice for decades. 
It was observed that these eight nurses remained free of COVID-19, even though they attended to several patients at the facility who were later diagnosed with COVID-19. RT-PCR tests on them remained negative. We followed them closely till December 2020. While they remained free of the disease, 62 of their colleagues working in less risky areas of the hospital and clothed in scrubs like those at the emergency department but not using hydrogen peroxide, had COVID-19 by the end of December 2020.
Between December 2020 and January 2021, Ghana recorded two new variants of SARS-CoV-2 (the Alpha and Beta variants) which caused a spike in COVID-19 cases till March 2021. 
Realizing that their eight colleagues who managed patients, before they were diagnosed as COVID-19 and transferred to COVID-19 treatment centers, remained protected from the disease because they were using hydrogen peroxide, 86 other colleagues at that hospital decided to try it. From January to end of March 2021, none of these 86 healthcare workers now using hydrogen peroxide plus the 8 emergency nurses contracted COVID-19, while 10 of their colleagues not using hydrogen peroxide had the disease.
Between April and December 2021, 424 members of staff out of a total establishment of 502 at the Shai-Osudoku District hospital were fully vaccinated with the Oxford Astra-Zeneca vaccine: 78 healthcare workers were not vaccinated. Within that period too, the number of staff using hydrogen peroxide decreased from 94 to 57. Of the 57 using hydrogen peroxide, 34 were vaccinated and 23 were not; none of them developed COVID-19.
Of the remaining 55 unvaccinated staff who were not using hydrogen peroxide, 35 had COVID-19 between April and December 2021. Of the 390 fully vaccinated staff not using hydrogen peroxide, 53 tested positive for COVID-19. The above information has been published elsewhere. [17,18]
These results were highly statistically significant.
New information from the Shai-Osudoku District Hospital reveals that there were 21 new cases of COVID-19 recorded among the healthcare staff in June 2022. Prior to that, no new cases of COVID-19 were recorded since January 2022. All the twenty-one (21) affected healthcare workers were fully vaccinated and not using hydrogen peroxide.
At the Mount Olives Hospital which is a private facility in the Bono East Region of Ghana, another opportunity presented for observation of hydrogen peroxide protection against COVID-19. Twenty-two (22) cases of COVID-19 were recorded at this hospital for the first time in July 2020 and before hydrogen peroxide intervention. Seventeen (17) of these were healthcare workers, and five (5) were inpatients. Hydrogen peroxide prophylactic use among inpatients and staff was introduced in August 2020. Hydrogen peroxide use was also recommended for the healthcare staff on voluntary basis.
Between August 2020 and March 2021, no cases of COVID-19 were recorded among a total of 3,375 inpatients on hydrogen peroxide prophylaxis twice a day. Of the members of staff, no cases of COVID-19 were recorded among those (32) not using hydrogen peroxide. Of the 52 on hydrogen peroxide prophylaxis, two travelled outside the town for a week and did not use hydrogen peroxide during that period; those two contracted COVID-19. The rest were free from disease.
From April 2021 to December 2021 no cases of COVID-19 were recorded among inpatients (total 4726). Within the same period too, no cases of the disease were found among the healthcare staff, all of whom were fully vaccinated and using hydrogen peroxide, except one who stopped using hydrogen peroxide in the month of December and contracted the disease. Again, this has been captured in our recent publications. 
Recent information from this hospital is that no cases of COVID-19 have been recorded among healthcare workers and inpatients from January to June 2022. All healthcare workers (current total 89), and all inpatients (total 2,484 for the period) have continued on hydrogen peroxide prophylaxis, the staff remaining fully vaccinated.
A summary of the observations so far is that none at both institutions using hydrogen peroxide on a regular daily basis had COVID-19 over a period of 26 months since the study began. At the Mount Olives Hospital, three staff members who stopped or interrupted hydrogen peroxide use over the period of the study had COVID-19. Otherwise, no cases of COVID-19 were recorded after hydrogen peroxide prophylaxis was introduced. There was not a single case of COVID-19 among a total of 10,220 inpatients on hydrogen peroxide between August 2020 and June 2022.
That the 32 members of healthcare staff at the Mount Olives Hospital who in the first phase of the study (between August 2020 and March 2021) did not use hydrogen peroxide and yet remained free of COVID-19 is not entirely surprising. They most likely were protected by the large number of staff and patients using hydrogen peroxide prophylaxis, even though they could have come into contact with SARS-CoV-2 in the community. That observation may indicate that hydrogen peroxide antiseptics curtails nosocomial spread SARS-CoV-2.
An important observation which must not be overlooked is that within the period of the study (May 2020 to June 2022), the Wuhan SARS-CoV-2 and all its variants and subvariants (especially of the Omicron type) of concern were encountered. [40,41]
None of them, however, caused disease in healthcare workers or inpatients on hydrogen peroxide antisepsis. This suggests that hydrogen peroxide has been effective in preventing COVID-19, deactivating all the SARS-COV-2 variants and their subvariants of concern encountered so far. By its mechanism of action which has already been referred to, hydrogen peroxide would, in all likelihood, therefore, prevent disease by other viral variants of concern that might emerge.
We have also argued that if hydrogen peroxide protects individuals from being infected with the virus, it would also protect COVID-19 patients from infecting others, should these patients use it regularly. 
Clinical studies should be conducted to establish that convincingly. By that same logic, hydrogen peroxide use among COVID-19 patients including those with 'long COVID' and those convalescing from the disease, could be expected to protect such patients from being reinfected with the viruses they are shedding. In the current study, our attention was drawn to three individuals who became re-infected and had the disease within a period of three months of the first infections. Likely, this could have been avoided, if these individuals had used hydrogen peroxide after the first infection.
These convincing clinical observations should encourage the use of hydrogen peroxide on a wider scale, especially among healthcare workers. It is noted that some individuals might not be able to gargle or mouthwash effectively, such as children and those with neurological challenges like stroke. For these individuals, mouth, throat and nasal swabs or spray with hydrogen peroxide should suffice
. Finally, based on the growing evidence of hydrogen peroxide protection against COVID-19, we recommend its wider use to mitigate the pandemic.