CONTRA COSTA COUNTY, Calif. (KRON) — Contra Costa County discovered its first two cases of the “highly infectious” COVID-19 variant from the U.K.

The variant, called B.1.117, is easier to catch and is potentially more fatal, the county said.

“This is a reminder that even though COVID numbers are falling, we need to continue using all our tools to prevent another surge: wear masks in public, continue to physically distance, avoid both indoor and large gatherings, and get vaccinated when it’s your turn,” said Dr. Chris Farnitano, the county’s health officer.

Farnitano says it’s likely there are more cases of the UK variant in Contra Costa County.

According to the county, one of the infected people began displaying common COVID-19 symptoms such as cough and muscles aches and was able to isolate at home. The other Contra Costa resident reported having multiple symptoms, including runny nose, cough, headache and loss of smell and taste. 

Recent studies show that the Moderna, Pfizer and Johnson & Johnson vaccines currently authorized in the United States are protective against the new strains.