There are few nurses in the Zambian capital with the skills and experience of Alex Mulumba, who works in the operating room at a critical care hospital. But he has recently learned, through a barrage of social media posts and LinkedIn solicitations, that many faraway places are eager for his expertise, too — and will pay him far more than the $415 per month (including an $8 health risk bonus) he earns now.

Mulumba, 31, is considering those options, particularly Canada, where friends of his have immigrated and quickly found work. "You have to build something with your life,” he said.

Canada is among numerous wealthy nations, including the United States and United Kingdom, that are aggressively recruiting medical workers from the developing world to replenish a health care workforce drastically depleted by the COVID-19 pandemic. The urgency and strong pull from high-income nations — including countries such as Germany and Finland, which had not previously recruited health workers from abroad — has upended migration patterns and raised new questions about the ethics of recruitment from countries with weak health systems during a pandemic.