The sudden dismantling of China’s "zero-COVID" restrictions in December means hundreds of millions of people are headed home for the Lunar New Year holiday for the first time since 2019. The crush of travel risks supercharging the world’s biggest COVID-19 outbreak, spreading it to every corner of the country.

Travelers, from migrant workers to college students to educated urban elites, risk carrying the highly-infectious omicron strain with them to COVID-naive swaths of rural China that have managed to evade the pandemic — until now.

Known as the world’s biggest human migration, the holiday traditionally involves packed planes, trains, buses and ferries departing big cities along China’s prosperous eastern coast for remote hinterlands as workers reunite with their families ahead of the new lunar year, which begins on Sunday. This year, they may be bringing COVID-19 with them, and exposing their loved ones to it for the first time.