Detection of Coronavirus P.1 Variant Confirmed in Yolo County

Third Variant of Concern Identified Through Healthy Davis Together Community Testing Operation

Genome Center photo
Samples are processed at the UC Davis Genome Center’s COVID-19 testing laboratory. (Gregory Urquiaga/UC Davis)

News release from Healthy Davis Together, issued today (April 15).

As part of its free COVID-19 testing operations, Healthy Davis Together and the UC Davis Genome Center identified the first-known case of the P.1 variant of SARS-CoV-2, the virus that causes COVID-19, in Yolo County. The P.1 variant, which first emerged in Brazil, has been identified as a variant of concern by the U.S. Centers for Disease Control and Prevention.

P.1 is the third variant of concern confirmed in Davis, following the confirmation of B.1.351 on April 6 and B.1.1.7 in February. All three variants have higher transmission rates — meaning they spread more easily and increase in prevalence quickly. B.1.1.7 is now becoming the most common strain locally, similar to the pattern observed elsewhere. Every positive COVID-19 test conducted by Healthy Davis Together is automatically screened by the Genome Center for all currently known variants of concern so that immediate action can be taken to alert and protect the community.

“The detection of another highly transmissible variant is concerning, especially as things begin to open up again and more people are out and about,” said Aimee Sisson, Yolo County public health officer. “It’s as important as ever to adhere to public health measures, including masking, physical distancing and regular testing, to keep the transmission of the virus as low as possible while we accelerate our vaccination efforts.”

The individual who tested positive for the P.1 variant has been notified that they tested positive for SARS-CoV-2, and the individual is currently under isolation. Contact tracing efforts were started within a few days of sample collection and testing. This person is an adult who lives in Davis and had not been vaccinated for COVID-19. The test HDT uses to genotype virus samples is being done on the same instrument that the program uses to test saliva samples for SARS-CoV-2. The IntelliQube PCR System, which was designed as a genotyping instrument by LGC Biosearch Technologies, permits rapid genotyping of all positive samples. The P.1. variant, which emerged from Brazil, has now been detected in 31 states according to the CDC. California has reported 41 cases of P.1.

“Getting vaccinated is one of the most important things each of us can do” said Sheri Belafsky, medical director for Healthy Davis Together and director of the Medical Surveillance Program for UC Davis Health. “However, until most of the population has been vaccinated, variants like P.1. are a threat. Following public health guidance and getting tested weekly are the best tools we have to prevent the spread of COVID-19 and all of its variants until enough people have been vaccinated to stop the spread.”

With three highly contagious variants identified in the community, it’s important for people to continue following public health guidance, including:

  • Wear a mask/face covering; make sure it fits properly
  • Keep physical distance; at least 6 feet apart and more if possible
  • Practice good hand hygiene
  • Get tested at least weekly for COVID-19, even if you are asymptomatic
  • Avoid large crowds
  • Do activities outdoors whenever possible
  • Stay home if you feel sick
  • Get vaccinated when it is available to you

Healthy Davis Together and Yolo County have been collaborating throughout the pandemic on COVID-19 testing, vaccination, and education to help reduce the spread. All Yolo County residents 16+ are now eligible for a vaccine. County residents can sign up for a vaccination appointment through the State of California’s MyTurn system.

More information on the P.1 variant and other variants of concern is available from the CDC. Information about free COVID-19 testing provided by Healthy Davis Together and by Yolo County can be found at

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Healthy Davis Together is a joint project between UC Davis and the city of Davis to prevent the spread of COVID-19 in our community and facilitate a coordinated and gradual return to regular city activities and student life. Comments and questions are welcome at

Top photo: Samples are processed at the UC Davis Genome Center’s COVID-19 testing laboratory. (Gregory Urquiaga/UC Davis)

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