The newest variant, the B.1.617 variant first found in India, has been detected in cases in eight countries of the Americas, including Canada and the United States, he said.
One case is under investigation, and others with the variants were travelers in Panama and Argentina who had arrived from India or Europe. In the Caribbean, cases of the Indian variant have been detected in Aruba, Dutch St Maarten and the French department of Guadeloupe.
The B.117 prevalent in the United Kingdom has been found in cases reported in 34 countries or territories in the Americas, while the B.1.351 variant, most prevalent in SA, has been reported in 17.
Brazil's so-called Manaus variant P.1 has so far been detected in 21 countries, the WHO expert said.
"These variants have a greater capacity for transmission, but so far we have not found any collateral consequences," Mendez said. "The only worry is that they spread faster."
The variants are associated with higher mortality due to the increased number of cases of Covid-19 but not because the virus has mutated into a more lethal version, he said.