Read on Twitter
WORRIED—is COVID cases truly down? That’s because US #COVID19 testing has dropped precipitously. US’s case dropped -15% last week, yet testing volume has dropped faster: down over -30%. Bad sign.
If you test less
less cases. Thus—is epidemic still growing? Worried maybe yes. https://twitter.com/drericding/status/1305629428492521477
If you test less
less cases. Thus—is epidemic still growing? Worried maybe yes. https://twitter.com/drericding/status/1305629428492521477
2) US cases certainly slower than Israel and Spain but US testing down 30% (and lowest in 2 months) is worrisome. A lot of Us testing drop due to natural disaster, but can’t be due to just that alone.
3) Juggling testing volume vs cases is tricky to grasp. Here is a rule of thumb scenarios (all else equal):
A) Cases rise faster than testing rise epidemic maybe growing
B) Case rise slower than testing rise epidemic maybe not growing.
C) ... see next comment
A) Cases rise faster than testing rise
epidemic maybe growingB) Case rise slower than testing rise
epidemic maybe not growing.C) ... see next comment
4) ...Testing scenarios continued:
C) Case drop faster than testing drop epidemic maybe slowing.
D) Case drop slower than testing drop (like what is happening) epidemic maybe growing
Again, scenarios assume all else equal in terms of testing guidance/lab infrastructure.
C) Case drop faster than testing drop
epidemic maybe slowing. D) Case drop slower than testing drop (like what is happening)
epidemic maybe growingAgain, scenarios assume all else equal in terms of testing guidance/lab infrastructure.
5) Hospitalizations and deaths are lagging indicators. But they are more objective than cases. That said, hospitalizations of “currently hospitalized” is only down a little this past week, from 32k last Monday to 30k today. But nothing like the 15% case drop or 30% testing drop.
6) There can be other cycle reasons of course, like if fewer people truly sick, then demand for tests lower. Or if contact tracing is slowing/dropping, then testing possibly also lower, yet more cases escaping detection.
7) Also changing is that with more mask wearing, cases are becoming milder and asymptomatic, which yields lower testing demand given most people do PCR tests if they feel sick. But asymptomatic cases escaping detection is a worry. This is why we need rapid home antigen tests.
8) There seems to be some disagreement between datasets. @OurWorldInData is reporting much sharper testing drop than @COVID19Tracking https://twitter.com/covid19tracking/status/1305647576939520000
