Global disease experts say little is known about China's experience with long-term COVID effects thought to have afflicted millions with debilitating fatigue, brain fog and other symptoms
The country is among the first few countries to recommend boosters for that age group, following Germany, the United States, Israel and Hungary.
Many countries are expanding COVID-19 vaccine booster programmes or shortening the gap between shots as governments scramble to shore up protection against the rapidly spreading Omicron variant.
Studies have shown an initial course of COVID-19 vaccines - typically given in two doses - may not be enough to halt infection from Omicron, but a booster shot may help.
The World Health Organization has said in recent months that administering primary doses - rather than boosters - should be the priority, though it has recommended boosters for those with health issues or who received an inactivated vaccine.