Even if there is a good answer to "How do we measure it?" it might cost more to know than it does to administer a third shot. There remains an argument (or a "

Even if there is a good answer to "How do we measure it?" it might cost more to know than it does to administer a third shot. There remains an argument (or a "rebuke," as the article puts it) that first world countries that are well placed to administer booster shots to the fully vaccinated should instead contribute to faster vaccination worldwide, even on a self-interested basis in order to reduce the cases where new variants can emerge. But that is a tenuous argument. A simple first question unanswered in the article is: How much of the unvaccinated population lives where vaccines requiring ULT freezers can be distributed? It may be that every place well equipped to use those kinds of vaccines will do best to get their total vaccination rate as high as possible and administer booster shots to reduce breakthrough infections, so normal activity can resume. Supply chain disruption is not a trivial problem. Having safe workplaces is not a luxury.