Re:Please poke holes in my Covid-19 math (SF Bay Area)
by mcguire on Sunday March 15, 2020 @03:45PM
(#22586086)
"The Bay area currently has 204 confirmed cases (as of 3/15). Multiplying that by either 10x or 50x (Harvard's estimated ratio of confirmed:unconfirmed cases) to get the actual number of confirmed cases today: 2,040 - 10,200 actual current cases in the Bay area."
Er, ah, uh, .... Multiply 204 cases by an estimated ratio of confirmed to unconfirmed cases of 10 to 50 gives 2040 - 10,200 estimated current cases in the Bay Area.
"Just because if I multiply by a 50x ratio, it returns a number larger than the 7.8MM total residents in the Bay area."
As you just discovered, a raw exponential increase cannot continue for very long, if only because infected individuals begin to have difficulty finding uninfected individuals to infect.
"80% of those will be "mild" which means "possibly as bad as having pneumonia but not needing a hostpital stay." 14% will require a hospital bed."
You may want to knock down the severity numbers a bit, since it seems likely that severe cases will be reported and confirmed in larger numbers than less severe cases.
"Potentially, even assuming aggressive social distancing, the Bay area needs 11x more beds than it has available in the next 30 days."
You probably should do this calculation in terms of bed-days: how long a given case occupies a bed on average before release/death.
Finally, as far as I know, the severity for old and infirm cases is much, much higher than the severity for those of you who are young and healthy. You may want to modify your model for local demographics.
Er, ah, uh, .... Multiply 204 cases by an estimated ratio of confirmed to unconfirmed cases of 10 to 50 gives 2040 - 10,200 estimated current cases in the Bay Area.
"Just because if I multiply by a 50x ratio, it returns a number larger than the 7.8MM total residents in the Bay area."
As you just discovered, a raw exponential increase cannot continue for very long, if only because infected individuals begin to have difficulty finding uninfected individuals to infect.
"80% of those will be "mild" which means "possibly as bad as having pneumonia but not needing a hostpital stay." 14% will require a hospital bed."
You may want to knock down the severity numbers a bit, since it seems likely that severe cases will be reported and confirmed in larger numbers than less severe cases.
"Potentially, even assuming aggressive social distancing, the Bay area needs 11x more beds than it has available in the next 30 days."
You probably should do this calculation in terms of bed-days: how long a given case occupies a bed on average before release/death.
Finally, as far as I know, the severity for old and infirm cases is much, much higher than the severity for those of you who are young and healthy. You may want to modify your model for local demographics.