CONTRA COSTA COUNTY (CBS SF) – Health officials in Contra Costa County confirmed their first cases of the more contagious B117 variant of COVID-19 in the county Tuesday.

Officials said laboratory results revealed two cases of B117, also known as the U.K. variant. One person infected with the variant began displaying common COVID-19 symptoms and was able to isolate at home, while the other reported multiple symptoms, including runny nose, cough, headache and new loss of smell and taste.

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Additional details about the people infected was not released.

“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.

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Farnitano said there are likely more cases of the variant in the community that have not been detected. “We can’t say how widespread it is in Contra Costa, but it’s concerning,” he said.

The news comes as Contra Costa re-entered the Red Tier over the weekend due to an ongoing drop in cases, hospitalizations and deaths from COVID-19. Under the Red Tier, restaurants, movie theaters, gyms and museums are among the sectors that can reopen indoor operations with capacity restrictions.

While more contagious, the health officer noted that initial studies of the three approved vaccines suggest they provide strong protection against the variant and other strains. Officials also urge people to wear two masks in public to prevent the spread of the variant.

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Farnitano said as of last week that more than 27% of county residents, about 370,000 people, have received at least one dose of the vaccine and that the county expects a “significant” increase in vaccines in the coming weeks.