After Alameda County identified possible cases of a COVID-19 variant that was discovered in the United Kingdom last week, California Gov. Gavin Newsom announced the first Bay Area cases of a variant from South Africa Wednesday.

One case of the B.1.351 variant was detected in Alameda County while the other was detected in Santa Clara, Newsom said during a press conference. The two cases were identified through tests done at Stanford University.

“Yesterday, I also said, we hadn’t identified any South African variants,” Newsom said during the press conference. “That’s no longer true, as of a few hours ago we have the first reported cases of South African variants.”

These cases follow six confirmed or suspected cases of the variant first identified in the U.K., termed the B.1.1.7 variant.

According to a recent UC Berkeley study, mutated strains are a concern among epidemiologists as these variants are known to be more contagious and easily spread compared to the original COVID-19 strain.

The B.1.351 variant, according to a Centers for Disease Control and Prevention update, developed independently from the B.1.1.7 variant, but both variants share some mutations. The B.1.351 variant was first reported in the United States in January.

“We currently, as I speak to you, we have 159 identifiable cases of the U.K variant in the state,” Newsom said during the press conference. “We have 1,203 identifiable West Coast variants in the state. There are two types of West Coast variants.”