Scientists in Oregon have spotted a homegrown version of a fast-spreading variant of the coronavirus that first surfaced in Britain — but now it’s combined with a mutation that may make the variant less susceptible to vaccines.

The researchers have so far found just a single case of this formidable combination, but genetic analysis suggested that the variant had been acquired in the community and did not arise in the patient…

Lab studies and clinical trials in South Africa indicate that the Eek mutation renders the current vaccines less effective by blunting the body’s immune response. (The vaccines still work, but the findings are worrying enough that Pfizer-BioNTech and Moderna have begun testing new versions of their vaccines designed to defeat the variant found in South Africa.)…

O’Roak and his colleagues found the variant among coronavirus samples collected by the Oregon State Public Health Lab across the state, including some from an outbreak in a health care setting. Of the 13 test results they analyzed, 10 turned out to be B.1.1.7 alone, and one the combination.