Discussing our suggestion for preventive throat disinfection to counter the Coronavirus pandemic1 with colleagues in the medical community as well as in academia has yielded positive feedback as well as objections, and has led to additional thoughts. And while in recent weeks we have been, and still are, focused on establishing and comprehending as deeply as possible the immunological “big picture” in viral epidemics and beyond from so far only partly interconnected evidence in the specialist literature, in order to derive actionable recommendations, we briefly summarize below what has emerged with regard to our first article since it appeared.
Viral load and disease severity
There are strong indications that viral load in the throat correlates with disease severity in COVID-19.2 In addition, it has been hypothesized for influenza3 that disease severity correlates positively with the number of contacts an infected person has with other infected persons, put the other way around, that separation from virus spreaders helps in healing. This seems to indicate that minimizing viral load in general should help in safely conquering viral infections of the respiratory tract. Viral load specifically in the throat is set to mean virus that is still or again (after secretion from, or death and subsequent disintegration of, infected cells) outside of body cells in which it can replicate and adversely regulate body functions.
Yet, as hypothesized by Professor Drosten of Charité Berlin, the initial massive replication of the novel Coronavirus in the throat, ensuring early significant exposure of the virus to Waldeyer’s4 tonsillar ring – considered “the first line of defense against exogenous aggressors”5 -, primes the immune system early in the course of the infection such that it is better prepared should the infection affect the lungs in a meaningful way. This may explain why, on a relative basis, COVID-19 is far less deadly than was SARS 2003, where the virus was detectable in the throat only in about 30 % of cases during the first few days and in about 60 % of cases by the time the lungs were already meaningfully affected,6 the latter most presumably because virus was transported up to the throat within lung sputum.
These two points, taken together, should sufficiently explain why an objection we have encountered, also among colleagues in the medical community, along the lines that “once the virus has struck, and entered body cells, the damage is done, and employing antiviral disinfectants in the throat won’t help anymore,” appears misplaced. If an infection cannot be prevented altogether, it can be beneficial that the virus is present to some extent in cells of a body area that is particularly immunocompetent, in order to introduce the immune system to the enemy in a significant way as early as possible and thus expedite development of the immune response, while at the same time destroying most virus copies outside of cells so that those copies cannot infect additional cells in the throat and – mostly via nightly aspiration of infected mucus from the throat during sleep – eventually the lung.
We would again like to emphasize that evidence shows that the deeper the sleep, the bigger the risk of aspiration of pharyngeal mucus to the lungs.7 Since sleep in the first part of the night, the slow wave (“deep”) sleep phase, is deepest, this is the most “dangerous” part of the night, so that much should be helped if the viral population present in the throat is destroyed immediately before going to sleep.
And may we allow ourselves the comment that if a viral infection is considered, in response to our suggestion, as simply an “intracellular” problem, then why try to develop vaccines against COVID-19, when the resulting antibodies bind to the virus (if, of course, not only in the throat) just as much exclusively outside of cells as the disinfectant destroys it?
One former fellow student and now department head at Charité Berlin told us our suggestion would not work because the destroyed viral load would “be recreated within 20 minutes”. Sifting through the literature, we found no evidence supporting this claim yet several indications from industrial virus production settings that it should definitely take more than the time the slow wave sleep phase lasts to rebuild what the disinfectant destroyed. The distinct aftertaste of gargling with hydrogen peroxide, even after rinsing, may even suggest that some potentially effective rest of the gargling solution will be present in the throat for some time during the initial phase of the night.
While watching the press conference presenting the Gangelt study by Professor Streeck and others8 we could not help but notice the logical inconsistency in the stance of public health officials stating that their primary aim was “to minimize viral load” in order to reduce disease severity and additional deadly outcomes from COVID-19, but then focusing entirely on advocating surface disinfection, all the while Professor Streeck had already clearly stated publicly9 (essentially affirmed by essentially every virologist we have read or heard) that even in very heavily infected households his team had never been able to isolate “living”, infectious virus from any surface they had taken swabs from. While at the same time the virus is clearly “living” in the throat as its initial primary “distribution center” from which it should be removed as much as feasible, in our view.
Countering pneumonia progression
Possibly the most important expansion to our thoughts (for which we thank Bruce L. Davidson MD, MPH, Seattle) regards the scope of the likely benefit from regular throat disinfection during a viral epidemic. We suggested doing this to minimize lung involvement from an infection, by preventing that the virus enter the lungs in large quantities via eventual aspiration of pharyngeal mucus from the throat to the lungs.10
If one contemplates the highly branched macro- (see the sketch above) as well as the micro-anatomy of the lungs, geared towards transporting everything foreign back up towards the throat to then be either spit out or swallowed, and the radiological evidence of how pneumonia develops in SARS-COV-like disease, one cannot help but consider it highly likely that the initial lung foci multiply, at least in part and in earlier stages, when virus present in those foci is transported back up to the throat in lung sputum and then re-aspirated to other, previously unaffected parts of the lungs, potentially dependent on sleeping position during the time of aspiration.
Normally aspiration of small amounts of infected mucus during pneumonia does not matter much because the patient is receiving systemic antimicrobial therapy. But a pathogen specific for alveolar cells (alveolar type II11) and some lower airway cells with no effective antimicrobial therapy (such as the novel Coronavirus) can, in the way described above, infect new areas and thus reduce the lungs’ oxygenation capacity in previously unaffected lung regions.
Disinfecting the throat daily and preventively (because in rare cases lung involvement may occur even before the onset of recognizable symptoms) during viral epidemics in the way we have suggested may thus help not only in pneumonia prevention, but also in countering its progression should one have developed already.
Implication of other organs as an argument against the usefulness of throat disinfection
Finally, we encountered the argument that phenomena such as loss of taste and smell, affection of the gastro-intestinal tract, of the kidneys and the heart have been reported, so that disinfecting the throat would be essentially useless.
Loss of taste and smell happen in the mouth and nose where the virus initially resides, and where our suggestion seeks to counter viral spread. The phenomenon is reported to be transient, and no one dies of it.
The gastro-intestinal tract is affected through swallowing mucus, and lowering the viral load this mucus carries is what our suggestion is about. In addition, no one has been reported to have died of COVID-19-induced nausea or diarrhea, and avoiding death from the infection is all that is needed to conquer COVID-19.
The kidneys and the heart are affected as a consequence of systemic inflammation resulting from pneumonia, exactly the condition we want to prevent or at least render less severe and non-lethal.
In summary, we believe it would be a good idea, also with a view to potential future viral epi- and pandemics, if the CDC and the WHO endorsed our suggestion so as to make it effective on a global scale.
The one objection we could imagine is that the CDC and the WHO only dare endorse measures that have been successfully tested in a clinical setting, even if common sense and decades of experience in the dental arena say that no risk worth mentioning is associated with throat disinfection in the way we have described. Surprisingly, a clinical trial as to the effectiveness of our suggestion has never been conducted,12 despite a number of current and especially retired medical practitioners calling it “a good idea” and an “old-fashioned method”, implying it has been practiced before. We therefore suggest it be clinically tested in a large-scale clinical trial in different age cohorts as soon as possible._____
- Some additional evidence as to the extent such aspiration happens during sleep: https://pubmed.ncbi.nlm.nih.gov/9149581/; https://pubmed.ncbi.nlm.nih.gov/15179196/
- The study in Guangdong, PRC, that we have previously referred to appears to have a different objective and to not even be actively recruiting at this time: http://www.chictr.org.cn/showprojen.aspx?proj=50660