The World Health Organization and the Centers for Disease Control and Prevention are out of step in their COVID-19 mask guidance, prompting confusion.

In light of sky-rocketing cases of the COVID-19 Delta variant around the globe, last week the WHO called for all vaccinated people to continue to wear masks.

The CDC, however, has not followed suit. The U.S. agency still sticks by its guidance -- announced in May -- for vaccinated people to relinquish their masks in indoor and outdoor settings, so long as it's been two weeks after their last shot of the vaccine. Unvaccinated people are supposed to continue wearing their masks and social distancing.

Why is the WHO advising masks for vaccinated people?

At a press conference on Friday, the WHO said that the rise of new variants made it necessary to pull out all the stops against the virus, particularly in places that had let down their guard.