2021-10-13 General

Diagnosis / Equity

This Twitter thread suggests that the reason darker-skinned people have higher fatality rates from COVID-19 is because, well, they have darker skin: pulse oximeters, which are used to judge how serious a case is, don’t work on dark-skinned people.

Economic effects

This video from January 2021 makes the economic case — not the moral case — that rich countries should work hard at making sure that all countries get vaccinated. Basically, the economies of all countries are so tied together that disruptions in the unvaccinated countries (due to labour shortages and/or lockdowns) will disrupt activities in the rich countries.

We are seeing major disruptions in supply chains now, so I think they were on to something. I worry that it’s only going to get worse.

Mitigation Measures

This article says that the Government of Canada is working on a pan-Canadian vax passport. They are hoping to roll it out before the end of October.

Unforeseen consequences

This article says that workplace meetings doubled during the pandemic.


This article says that SARS-CoV-2 can infect lots of kinds of felines, ferrets and their cousins, deer, mice, hamsters, most bats, some monkeys, and sometimes dogs and cows. It doesn’t seem to infect raccoons, pigs, squirrels, prairie dogs, or birds. (This is an incomplete list!)


This preprint from the US looked at antibody levels after a booster (e.g. a third shot after two doses of Spikevax), mixing and matching the brands of the boosters. The gamma globulin serum binding antibody levels (in Binding Antibody Units/mL) 15 days after the booster, in International Units per microlitre were:

J&J primarySpikevax primaryComirnaty primary
J&J booster326.03029.41904.7
Spikevax booster3203.16799.86155.0
Comirnaty booster2549.55195.63409.1

The study authors said basically that mixing was good, but looking at this table, my conclusion is that Spikevax (Moderna) is good. Note, however, that this study was done with a full dose of Spikevax, not the half-dose booster that Moderna is requesting authorization for.

Other tables — for the neutralizing antibody titres, for measurements at different times after the booster — showed similar results.

Note that the authors disclosed some pretty significant limitations on the study: it was small — they say too small to compare between groups — and not randomized. So don’t bet the farm based on this study.


This review article preprint found that 54% of people had Long COVID symptoms after six months. (Caveats: the median age was 54.4 and 79% of the people in the study had been hospitalized.)

Recommended Reading

Remember 5-micron droplets, and how COVID-19 spread through droplets? This article talks about the investigation required to figure out where the 5-micron figure came from. Spoiler: it was a mistake.