HONG KONG—As Chinese authorities voiced confidence they were containing the country’s coronavirus outbreak, the official Xinhua News Agency meticulously chronicled President Xi Jinping’s personal battle against the epidemic—from visiting front-line medical workers to fielding calls from foreign leaders.

In a glowing article published this past week, the state-run media organization concluded that Mr. Xi’s dedication proved he has a “pure heart like a newborn’s that always puts the people as his number one priority.”

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