Day 147: Is it the Air-Conditioning?

The US has reached 2.5 million cases, with 126,000 dead and a million recovered. While summer is being kind to the hard-hit Northeast, things are not going so well in warmer places. California, once a coronavirus success story, has surpassed 200,000 cases. The ICUs of Texas are upon the news, as is the situation in Arizona and Florida. While many other states are also on the rise, none of them, not even CA/TX/AZ/FL, are anywhere near the case rate or death rate of previously hard-hit states.

Everyone has noted the lower ages and milder disease progress of the disease in the currently surging states. The usual reaction is, nevertheless, to blame the victim-states for insufficient social distancing and mask-wearing (wholly independently of any statistical evidence of such) and the federal government for policies that have not changed much yet somehow managed to selectively slay old New Yorkers in the spring and hospitalize young Houstonians in the summer. Setting aside for the moment the dangers of blaming victims for their failure to abstain from all human contact, PlagueBlog notes a disturbing lack of scientific curiosity about what's actually going on here.

Some have at least asked whether the retreat into air conditioning for the summer typical of the most affected states is as dangerous as working in a chilly meat-packing plant. NBC News answers this question with a firm no:

But experts say there’s little evidence to link air conditioning to the spread of the coronavirus. Rather, the risk more likely comes from the amount of time spent indoors in close proximity to others.

“The opening up of facilities from my point of view, and I think this is shared by colleagues, that doesn't depend on the air conditioning, it's the gathering of the people for long periods of time,” said Dr. William Schaffner, a professor of preventive medicine and infectious diseases at the Vanderbilt University Medical Center.

“You can think of laboratory experiments and theoretical possibilities of how air conditioning might spread this virus, but so far, there really isn't any noteworthy evidence that this is happening,” he said.

PlagueBlog believes the clues are all there in the case rates. It seems you cannot hide from an uncured respiratory disease forever; it's not clear that you can hide at all. Maybe all you can do is pretend that your mild winter weather is actually an amazing success story for the half-hearted lockdown measures that it turns out you can't actually lift without having an eventual resurgence of cases—because your numbers were all the luck of the superspreaders and the weather to begin with.

That is, the only way to herd immunity is herd immunity, and some of us are already there because our weather was too cold or our superspreaders too super to successfully hide from the flu a coronavirus. Those who aren't there yet are now or will soon be facing the same old choice of trying to slow the virus down enough to preserve emergency room capacity, or not. (PlagueBlog does not recommend slowing it down until it's winter again, since summer COVID-19 outcomes seem to be much better so far.) On the bright side, it doesn't seem to take all that much herd immunity to knock the virus out; according to this May preprint, 10–20% immunity may be enough to do it.

Massachusetts cases are up a fifth of a percentage point again today. The New York Times article on the final report about the Holyoke Soldiers Home is at once damning and confusing. While it's clearer what went wrong, why is still a mystery; who gave the crazy orders and what they possibly could have been thinking or trying to accomplish with them remains unclear.