Day 118: Killed by the Common Cold

The world is at 5.825 million cases. Russia, at #3, is nearing 380,000 cases, and Brazil (#2) is approaching 415,000 cases. Can Brazil eventually steal our #1 spot? The population of Brazil is about two thirds that of the US, and it's about to be winter there. On the other hand, in tropical areas of Brazil the rainy season (which is their flu season) is ending now. Brazil ought to be approaching the "brick wall" that the pandemic seems to hit after about 70 days in every country, regardless of local lockdowns and social distancing practices, but the pattern doesn't seem to hold in the latest South American outbreaks (Brazil, Peru, and Chile). That is, there's no evidence of a peak around 35 days followed by a decline, perhaps because of the slow start to their local epidemics. So there's unknown potential there.

Here in the US (1.75 million cases), meteorological summer is days away, and we've also hit the brick wall. (You know you've hit the wall when #4 Illinois, of all places, qualifies to reopen.) There's also some news out of Florida about who was actually dying down there.

Details on 2,017 deaths from coronavirus in Florida were released Thursday, after a threat of legal action against the state by media organizations.

The reports, produced by county medical examiners, show the dead ranged in age from 26 to 104 and were predominantly elderly. A third of the victims were diabetic. Twenty-seven [1%] were under the age of 40, most suffering from preexisting health problems. [...] The most common was obesity, followed by diabetes and hypertension. Several had more than one of these.

On the common cold front, there's a pre-proof out from Cell with the rather uninformative title Targets of T cell responses to SARS-CoV-2 coronavirus in humans with COVID-19 disease and unexposed individuals [PDF]. Though mainly about their research into T-cell responses in milder cases of COVID-19, the paper also makes some interesting comparisons to similar cross-reactivity research into the 2009 H1N1 influenza pandemic. Though the text is pretty opaque as these things go, this line from the summary says a lot:

Importantly, we detected SARS-CoV-2−reactive CD4⁺ T cells in ~40-60% of unexposed individuals, suggesting cross-reactive T cell recognition between circulating ‘common cold’ coronaviruses and SARS-CoV-2.

What this actually means is that the brick wall may, in fact, be herd immunity provided by previous exposure to other coronaviruses. Also the great mystery of different pandemic outcomes in different countries may have far more to do with circulating cold strains than with the severity of your lockdown or more exotic theories like off-target vaccination protection.

The Blaze reports on the implications of this paper:

On the one hand, this virus seems to be extremely contagious and transmissible. On the other hand, it appears to have been around for a while, possibly in December, and didn't kill too many people until super-spreading events in March.

On the one hand, the virus seems to kill a lot of vulnerable people for several weeks. But then it peaks after six weeks or so and nearly disappears a month or so later. We've seen the same curve in every country, almost as if it hits a brick wall and then runs out of steam.

[...] Perhaps, it could also explain why there appears to be a massive gap in severity of the virus in Asia vs. Western countries. Asian countries are regularly exposed to coronaviruses.

P.S. Massachusetts cases were up 0.7% today—not exactly grounds for cancelling the Boston Marathon (previously postponed to September), but they did it anyway.