Effectiveness of saline water against respiratory tract viruses

[Wrichik Basu]

TL;DR Summary

My question is not focussed on SARS-CoV-2, but respiratory tract viruses in general. How effective is saline water against such viruses?

Since the outbreak of COVID-19, many people, including some doctors, have been saying that gargling with salt water is effective against SARS-CoV-2. The theory rolled out is that the virus "stays" in the nasopharyngeal tract for some time before going into the lungs, and rinsing the tract with saline water will kill the virus. A simple Google search reveals that this claim is not supported by any evidence.

My question is not focussed on SARS-CoV-2, but viruses in general. How much effective is saline water against viruses that enter the body through respiratory tract?

I know that saline water can kill bacteria by osmosis. The cell is dehydrated, leading to enzyme and protein malfunction, thereby causing cell death.

But this process is not applicable for viruses. From my little knowledge in this field, viruses do not have any ribosome, so there arises no question of creating any protein unless they attach themselves to a host cell. They don't have any cell sap that can simply be dehydrated. In naive words, if I experimentally "dip" a virus in saline water, it will not lose its capability of attacking other cells. The host cell may dehydrate and die, but respiratory tract viruses generally do not attack host cells in large numbers and start multiplication till they have reached the trachea, where saline water cannot reach. Am I correct in saying these?

 

[jim mcnamara]

Other than a possible lavage: treating a virus upper repsiratory infection with a saline wash may alleviate irritation and flush off virus particles, there is no major patient benefit AFAIK. You should probably consider the placebo effect, too.

This may not apply: when virus is first introduced there is sort of a dose response curve. More virus particle exposure increases severity and speed of infection. Less may reduce the severity and increase onset time - because the immune system has more time to work before the virus infection is full blown. This is one reason why surgeons and health care people wear masks - a modicum of self-protection and patient protection. Masks reduce exposure. There is no research including case studies that makes absolute statements about this. It is one of those medical things that professionals see.

So assuming you flush very soon after infection, washing away "loose" virus particles may do what I just described - make the disease process less severe. Drawback: humans do not do things like this until they have symptoms. Too late. Example: Would you flush your nose and throat 5 times a day every day? For the rest of your life?

 

[256bits]

I know that saline water can kill bacteria by osmosis

Blanket statements - there are always possible exceptions to any "general rule" that may be crafted.
Example - a deadly salt water bacteria
https://en.wikipedia.org/wiki/Vibrio_vulnificus#:~:text=Vibrio vulnificus is a species,Infection with V.

and rinsing the tract with saline water will kill the virus

That's ad hoc. - Shame on them.
It could just as well be that an electrolytic solution is necessary for adsorption of the virus into the host cell.
In which case rinsing with clean water ( or distilled water ) could be more effective.