Mexico tourism and hotel officials say the rate of positive tests among travelers since the new testing requirement went into effect is minimal. The Grand at Moon Palace, a luxury all-inclusive resort in Cancun, has had no more than 10 cases, according to Cesar Fallardi, director of operations. Together with sister Palace Resorts, the rate is 0.4% he said.

"It's nothing, honestly, nothing,'' he said.

In Los Cabos, another popular beach destination in Mexico, Pueblo Bonito's five resorts have had 23 positive results out of 8,196 tests, according to marketing director Mary Van Den Heuvel.