The arrival of the Omicron variant of the coronavirus is a blow for governments around the world that were banking on foreign workers to help ease labor shortages pinching their economies.

The new variant has triggered travel bans and tighter restrictions on new arrivals in dozens of countries, slamming the brakes on a reopening that had been gathering pace as vaccination coverage increased and economic growth accelerated. That has resulted in a pause on a widespread effort by many advanced economies to entice foreign workers to their shores.