Next thread: relative infectiousness via mask samples. tl;dr: I'm probably at least 5000x less contagious yesterday (day 8 of symptoms, day 5 of Paxlovid) than I was on day 2 (peak).
x.com/famulare_mike/status/1894899637217304636
As I lazily described here, you can do some simple image processing to make rapid tests quantitative x.com/famulare_mike/status/1894899668787818579
And here I showed how to test an n-95 for exhaled virus x.com/famulare_mike/status/1893095706396946940
So we can put these together and compare exhaled viral load changes with nasal/throat swab changes, to get as close a proxy for contagiousness as possible!
Unfortunately, I only have two good mask samples (because I wasn't planning on doing this quantitative stuff until a few days ago).
- 1 hour on day 2 of symptoms when I was red hot by nose
- 11 hours yesterday (day 8) when I was still faintly positive at ~200x lower viral load
The day 2 mask after an hour was positive, solidly at the mouth and juuuust barely at the top by the nose, out of the jet zone. (The side sample looks negative by eye, but the brightness dips very slightly, from background ~140/255 to test ~137/255, as seen with a color picker.)
The day 8 mask, even after 11 hours, was NEGATIVE negative. No signal from background at all.
So, just for fun, the figures below shows the precise estimate for the relative viral load for the nose and mask on day 8 vs day 2, and the upper bound for the mask
As you can see, quantitatively, I’m at least 5000x less contagious via the air than yesterday (and possibly infinitely less). So, I am very very likely no longer contagious! I’m also at least 70x less infectious by saliva. So I probably can't infect anyone else now!
I will mask until twice negative on the nose because why not? (Also, gotta watch for rebound!)
How cool is it to have quantitative measures of contagiousness?! With an app reader for the image processing, and instructions for mask testing, everyone could have this.
With more rigorous correlation of antigen test color, pcr ct, and existing studies correlated ct with transmission, we could have quantitative transmission risk measures for anyone who tests. Beyond satisfying my curiosity, I hope having these examples will help me advocate.
Addendum: I'm out of FlowFlex and iHealth tests, so I got a few crappy BinaxNow (I can't get a solid control line on these...), and I'm nose/thoat negative on Day 9.5. The upper bound is probably above my last two FlowFlex, so not sure what to make of it.
Still tired and taking daily naps, but otherwise fine. Fingers crossed I throw a few more negatives and I'm freed on Monday.
The Mrs is doing well too, but still testing quantitatively more positive than me.
Daughter holding negative. Thanks masks, HEPAs, and windows!
Mike Famulare
@famulare_mike
Like polio, Twitter lingers on. Learning to be a father, husband, and person. Systems epidemiologist, see Google Scholar. All tweets mine alone, not my employer
