It’s probably a leading indicator of COVID pneumonia but that probably still takes some days to develop during which time infected people are still contagious. Probably better to stay home or at least wear a mask...
COVID causes blood O2 to drop because it causes a viral pneumonia. Early stages of a viral pneumonia can be pre-symptomatic or entirely asymptomatic. Asymptomatic patients can still transmit COVID to others. Patients with low oxygen should seek medical attention because their pneumonia can get worse.
Your source says “Many patients with COVID-19 disease have low oxygen levels even when they are feeling well.” These patients have low oxygen because of COVID pneumonia.
Your (uncited) claim that "These patients have low oxygen because of COVID pneumonia." There are plenty of sources out there[1] that talk about a strange, again, leading indicator, known as "silent hypoxia" which has nothing to do with pneumonia. Further, there's a lot of confusion in your post: if COVID ends up giving you pneumonia, you are definitionally not asymptomatic.
You are mistaken. You can have pretty much any diagnosis and there is no “definitional” reason you must be symptomatic.
Pneumonia is a diagnosis (well, class of), not a symptom nor a sign, which are distinct terms of art. You can have pneumonia that shows up on a chest X-ray (a sign) without any symptoms.
A better example might be high blood pressure, which many people understand can be silent/asymptomatic for years but is easily measurable.
Point still stands, symptoms are noticeable and reportable by the patient. If covid gives you pneumonia you may still be asymptomatic.
> You can have pneumonia that shows up on a chest X-ray (a sign) without any symptoms.
Your post is a bit confusing, I'm not exactly sure what you're arguing. Walking pneumonia (which is what you're describing; the term of art is atypical pneumonia) is extremely rare, and it's not what we're talking about here. Non-atypical pneumonia has symptoms, ergo is by definition not asymptomatic.
