Friday, August 06, 2021

Wuhan Rt

 ... is just one interesting data point you can find at the CovidStim site cooperatively produced by Yale, Harvard and Stanford, proving that someone, somewhere, is still doing good STEM work. Rt is the effective reproduction rate of the WuFlu. If Rt is 1, it means each infected person will infect one more. If it's 2, then each infects 2 more and so on.

As Delta hysteria goes on, I've been clicking around a few data sites and discovered this one. It doesn't give fatality rates, but it does describe the spread. If you go there and mouse over the map, it will give you Rt as a function of county. Here's my own SoCal right now.

For those unfamiliar with our geography, I circled, from bottom to top, San Diego, Orange and Los Angeles counties.

What's interesting to me is something I saw as I looked at the map in general. It looks like rural counties have a higher Rt than urban ones. In the map above, San Diego, Anaheim and Los Angeles are all pretty benign while Imperial County to the east is getting clobbered.

Why would infection rates be worse where the population is sparse? Further, if I remember right, LA doesn't have a particularly good vaccine rate. If that's the case, why isn't it getting crushed? Does Rt go down as density goes up because there are so many infected people nearby, competing to infect a new host?

Beats me. Hmmm.

5 comments:

WC Varones said...

Probably lower vaccination rates and less exposure in earlier waves.

tim eisele said...

That's an interesting site, thanks! It's a little crashy, but presumably they'll get the bugs out over time.

Rural areas seem to be all over the place. Up here in the UP, Iron County has an Rt of only 0.62, while Baraga County right next door to it is 1.98. Just north, Houghton County is in-between at about 1.22, and Keweenaw County (furthest north) is back down to 0.59. And all of these are pretty rural. Baraga has the casino, and Houghton has the university.

If there is any pattern at all this summer, it is that the counties that have a lot of indoor locations that tourists frequent (restaurants, bars, casinos, and gift shops) have a higher infection rate, while those that are where the tourists mostly do outdoors things (biking, hiking, fishing, kayaking, etc.) are seeing very little.

What we saw in Houghton County last year was a very low infection rate until Michigan Tech went back into session in the fall, when it spiked immediately after the students came back to town. And after that, every time there was a break and students went home and came back, there was another spike. It's been pretty slow all summer, but if the pattern keeps up, we will get yet another spike in about four weeks

One Brow said...

Looking here, the vaccintion rate in Imperial County seems to be substantially lower than in it's western neighbors.

K T Cat said...

Tim, your explanation also works for what is happening in Dixie where anyone with a lick of sense is indoors right now, enjoying air conditioning.

Carl said...

@KT Cat
With all due respect, i would do some more fundamental reading before commenting on basic biology related to viral spread.
Free speech is great and there is some uncertainty but this is embarrassing.