Regarding the mouthwash, I agree that once the virus invades the LRT, it is useless. However many times COViD starts as URTI and it is localized to the nasopharyngeal mucosal epithelia. During this time, gargling could reduce viral load in the mouth thus reducing transmission risk and symptoms. Please check ELVIS trial out of university of Edinburgh. Same team is running similar trial for COVID. While I agree it won’t cure it, it might offer benefits when applied early in the infection cycle.
Thanks for pointing out that this has been studied elsewhere--I think this is worth noting, but I do think we should be clear on what's data and what's speculation.
I will concede the point that it is worth studying; there are certain limited conditions under which I could hypothesize--only hypothesize, mind--that use of mouthwash could help to limit an infection or otherwise make it abortive.
For example, mouthwash use within an hour of exposure might sanitize the mouth sufficiently to reduce the input dose before all potential local infection events have occurred. In this way, it might be mildly prophylactic. To my knowledge, this hasn't been demonstrated anywhere. The study that I was sharing didn't demonstrate this because it was not a clinical study.
I am familiar with the ELVIS study; it was a test of the effect of gargling on the transmission and duration of colds. I do not think that it is relatable to mouthwash. Hypertonic saline (aka really salty gargling water) is not the same thing as Listerine. There are a number of mechanisms that might explain why hypertonic saline gargling could affect disease course and transmission in the common cold, which is a purely upper respiratory illness. The common cold is not COVID-19, though, so I just don't think that these results are portable. We will have to see the results in ELVIS COVID-19 before making conclusions, and right now I do not think we have any data on this.
That said, mouthwash is not an antiviral drug. We have not seen it studied as one, and we cannot conclude from the currently available data that it will have any effect on COVID-19. By the time a person is infected, their cells are producing new virions at high rate. Mouthwash may help to destroy viruses present in the mouth, but it won't affect those in the nasopharyngeal space in its entirety, nor in the lungs. It will also not prevent the formation of new virions. It is possible that it could reduce the kinetics of spread through the body in an early infection, but again, we need an experiment to study this and we don't have one.
At the end of the day, hypotheses are cool. Speculation is interesting. Neither should inform behavior. The best way to deal with COVID-19 is to avoid getting it. If that fails, the next best way to deal with it is to seek the advice of a physician. But if you want to use mouthwash a couple times a day, I don't see how it could hurt if used as directed. It's generally safe for human use, or it wouldn't be on the market as mouthwash. Just don't drink it, inject it, or use it any other nonstandard way.
Regarding the mouthwash, I agree that once the virus invades the LRT, it is useless. However many times COViD starts as URTI and it is localized to the nasopharyngeal mucosal epithelia. During this time, gargling could reduce viral load in the mouth thus reducing transmission risk and symptoms. Please check ELVIS trial out of university of Edinburgh. Same team is running similar trial for COVID. While I agree it won’t cure it, it might offer benefits when applied early in the infection cycle.
Thanks for pointing out that this has been studied elsewhere--I think this is worth noting, but I do think we should be clear on what's data and what's speculation.
I will concede the point that it is worth studying; there are certain limited conditions under which I could hypothesize--only hypothesize, mind--that use of mouthwash could help to limit an infection or otherwise make it abortive.
For example, mouthwash use within an hour of exposure might sanitize the mouth sufficiently to reduce the input dose before all potential local infection events have occurred. In this way, it might be mildly prophylactic. To my knowledge, this hasn't been demonstrated anywhere. The study that I was sharing didn't demonstrate this because it was not a clinical study.
I am familiar with the ELVIS study; it was a test of the effect of gargling on the transmission and duration of colds. I do not think that it is relatable to mouthwash. Hypertonic saline (aka really salty gargling water) is not the same thing as Listerine. There are a number of mechanisms that might explain why hypertonic saline gargling could affect disease course and transmission in the common cold, which is a purely upper respiratory illness. The common cold is not COVID-19, though, so I just don't think that these results are portable. We will have to see the results in ELVIS COVID-19 before making conclusions, and right now I do not think we have any data on this.
That said, mouthwash is not an antiviral drug. We have not seen it studied as one, and we cannot conclude from the currently available data that it will have any effect on COVID-19. By the time a person is infected, their cells are producing new virions at high rate. Mouthwash may help to destroy viruses present in the mouth, but it won't affect those in the nasopharyngeal space in its entirety, nor in the lungs. It will also not prevent the formation of new virions. It is possible that it could reduce the kinetics of spread through the body in an early infection, but again, we need an experiment to study this and we don't have one.
At the end of the day, hypotheses are cool. Speculation is interesting. Neither should inform behavior. The best way to deal with COVID-19 is to avoid getting it. If that fails, the next best way to deal with it is to seek the advice of a physician. But if you want to use mouthwash a couple times a day, I don't see how it could hurt if used as directed. It's generally safe for human use, or it wouldn't be on the market as mouthwash. Just don't drink it, inject it, or use it any other nonstandard way.