I was reading about a viral list of dubious coronavirus tips on The Verge and reached this tip:
“Even if the virus gets into your mouth, drinking water or other liquids will wash them down through your throat and into the stomach. Once there, your stomach acid will kill all the virus,” one tip reads. Loren Rauch, an emergency room doctor in Los Angeles who has a master’s degree in epidemiology, told Mother Jones this advice was “totally bogus.”
I asked a friend, who has a PhD. in cell biology, about this and she said that it's true that a virus would be killed by the stomach acid (i.e. due to high acidity, or low pH value, of stomach acid which could easily break the structure of the virus); however, she added that it's NOT true to think that drinking water would wash the virus from your respiratory system (i.e. trachea or lungs) into your stomach, so drinking water regularly does not necessarily help if it's in your respiratory system.
I was a bit confused since the doctor referenced in the article considered the whole advice as totally false; on the other hand, my friend thinks at least part of the advice, i.e. the virus being killed by stomach acid, is true.
Now, my question is not limited to coronavirus and I am not seeking medical advice or treatment here. I just want to know if my friend is scientifically correct, i.e. whether stomach acid is able to destroy the biological structure of a virus (any virus, and not necessarily coronavirus)? And if so, how does this work biologically?