Day 150: The Second Wave

PlagueBlog has learned (via Reddit) that people in air-conditioning-dependent places don't realize how many of us do without. So the AC theory of the second American wave of coronavirus may not be obvious to those chilling in their central AC in the midst of it. On the other hand, it's not obvious to Europeans just how much the weather and the accommodations to it vary across the US.

To be brief, central AC is much more common in the South and West than in the Northeast or Northwest of the US. Some have explained the current surge in the US by the summer flight into air-conditioning. Though herd immunity could explain the current state of the Northeast, it can't explain the largely-unaffected Northwest.

The Harvard Gazette chimes in on the dangers of air conditioning:

“The states that, in June, are already using a lot of air conditioning because of high temperatures are also the places where there’s been greater increases in spread of COVID-19, suggesting more time indoors as temperatures rise,” Nardell said. “The same [thing] happens in wintertime, with more time indoors.”

Professor Nardell implies that the theory relies on some airborne transmission of coronavirus, but it's not clear why it would when wintertime contagion is not contingent on airborne (non-droplet) transmission. Perhaps there are just too many Texans infected for droplets to have done it absent winter weather.

Also joining in on the second wave (though probably not on account of air conditioning) is the Brazilian city of Belo Horizonte, capital of Minas Gerais. They closed non-essential businesses back on the 8th of April, relaxed their restrictions on the 25th of May, and today re-closed-up shop. What qualifies as essencial is always interesting; in Belo Horizonte paint shops, lumber mills, and lottery kiosks will remain open. Bakeries get to open at 5am rather than keep the standard hours of 7am to 9pm. Oddly enough, banks are included among the essential businesses that have no restrictions on the hours they can keep, along with the more standard exceptions of pharmacies and gas stations.

Massachusetts cases were up a tenth of a percentage point today. We are currently patting ourselves on the back for being one of four states that seem to have nearly recovered from the pandemic. (Who the other three are seems to depend on who's counting.)