BEIJING—U. S. and European leaders are looking at China’s progress in curbing the coronavirus pandemic to guide them on how to beat the virus within their own borders.

They may be drawing the wrong lessons, doctors and health experts say.

The cordon sanitaire that began around Wuhan and two nearby cities on Jan. 23 helped slow the virus’s transmission to other parts of China, but didn’t really stop it in Wuhan itself, these experts say. Instead, the virus kept spreading among family members in homes, in large part because hospitals were too overwhelmed to handle all the patients, according to doctors and patients there.

What really turned the tide in Wuhan was a shift after Feb. 2 to a more aggressive and systematic quarantine regime whereby suspected or mild cases—and even healthy close contacts of confirmed cases—were sent to makeshift hospitals and temporary quarantine centers.

The tactics required turning hundreds of hotels, schools and other places into quarantine centers, as well as building two new hospitals and creating 14 temporary ones in public buildings. It also underscored the importance of coronavirus testing capacity, which local authorities say was expanded from 200 tests a day in late January to 7,000 daily by mid-February.