For more than a month, the Centers for Disease Control and Prevention has been offering to send a team of experts to China to observe its coronavirus outbreak and help if it can.

Normally, teams from the agency’s Epidemic Intelligence Service can be in the air within 24 hours.

But no invitation has come — and no one can publicly explain why.

The World Health Organization, which made a similar offer about two weeks ago, appears to be facing the same cold shoulder, though a spokeswoman said it is just “sorting out arrangements.”

Current and former public health officials and diplomats, speaking anonymously for fear of upsetting diplomatic relations, said they believe the reluctance comes from China’s top leaders, who do not want the world to think they need outside help.