The Centers for Disease Control and Prevention confirmed the first detected case of the omicron variant Wednesday, less than a week after the World Health Organization designated the new COVID-19 strain a variant of concern.
The individual, after returning to California on Nov. 22 from a trip to South Africa, sought a test after exhibiting symptoms and received a positive diagnosis on Nov. 29. Despite the weeklong potential for transmission, none of the individual’s close contacts tested positive.
The individual was fully vaccinated, although it was unclear whether the person received a booster. The patient has mild symptoms but is improving.
The University of California, San Francisco had received the virus sample at 8 p.m. Tuesday and had sequenced nearly the entire genome by 4 a.m. CDC then confirmed the results.
White House chief medical adviser Anthony Fauci, speaking at a White House news conference, reiterated that the spike protein of the omicron variant has substantially more mutations than does that of the delta variant. That suggests the variant could be more transmissible or evade immune protection.
The variant has contributed to a surge of infections in the Gauteng Province of South Africa, which was already heavily hit by the delta variant. The prior infections might be expected to give people a high level of preexisting immunity. South African health authorities reported a 16.5 percent test positivity rate on Wednesday.
Nothing definitive about transmissibility or severity of disease will be known for at least a couple of weeks, Fauci said.
“We don’t have enough information right now,” Fauci said. “You will be reading a lot of tweets and a lot of comments about this, but it’s just too early to say.”
Fauci defended controversial bans on flights from countries in the southern region of Africa, while European countries and Israel that have also seen omicron cases have not seen shuttered travel.
"We did struggle with that," Fauci said. "We wanted to see if we could buy time temporarily. I do hope this gets sorted out and lifted before it has a significant impact."
Fauci expressed confidence that boosters could offer further protection against omicron because another dose ramps up antibodies, at least temporarily, which would supplement longer-lasting immune cells from prior vaccinations. The Biden administration has emphasized boosters as key to its strategy against the emerging variant over limiting public gatherings.
“When you get a high enough level of an immune protection, you get spillover protection even against variants the vaccine was not designed for,” Fauci said.
Amid the winter holidays, Fauci said that not wearing a mask is fine in private indoor settings with family members whose vaccination status you know, but that in public indoor places, people should wear masks.
Despite the threat omicron could pose to herd immunity, Fauci said he remained confident the pandemic will eventually come to a close.
“This will end, I can assure you that,” Fauci said.