Omicron Outbreak at a Wisconsin Wedding Infects 5 Vaccinated People in California

At least five vaccinated people in the San Francisco Bay Area have contracted the Omicron coronavirus variant after they attended a wedding in Wisconsin last month, according to public health officials.

The five people were among a group of 12 vaccinated adults who tested positive for COVID-19 after attending the wedding on November 27, the Alameda County Department of Health said Friday. One of those people had recently returned to the U.S. after traveling internationally, but the health department did not disclose where or when.

The individuals range in age from 18- to 49-years-old and most have received a coronavirus booster shot. Each person has so far been reported being mildly symptomatic and no one has been hospitalized.

Genomic sequencing is still being conducted to determine whether the remaining seven cases are the Omicron variant, according to the health department.

"Public health officials continue to be vigilant and are monitoring evidence of this variant's transmissibility and the severity of illness resulting from infection. We don't yet know how Omicron will impact a highly vaccinated region like the Bay Area. We remind residents that vaccination continues to provide the best protection against severe illness from COVID-19 that could result in hospitalization and death," the health department said in a statement Friday.

The Bay Area outbreak was reported just two days after the first U.S. Omicron case was discovered in San Francisco. By Saturday, at least 20 cases of the latest variant have been detected in more than 10 states.

Omicron was initially found in South Africa last month and labeled a variant of concern with a "very high" global risk level after scientists observed it has more than 30 mutations.

Little is still known about the new variant, but experts fear it may prove to be more transmissible than other versions of the virus or be capable of bypassing certain levels of immunity. Early data from South Africa has suggested that Omicron spreads twice as fast as the coronavirus Delta variant.

So far, those who have tested positive for Omicron in the U.S. have ranged in age and vaccination status, but all shown mild to moderate symptoms and none have been hospitalized, CNBC reported.

White House COVID-19 Response Coordinator Jeff Zients said in a statement this week that the U.S. is prepared to meet Omicron "with science and speed," and urged Americans to get vaccinated.

"The President's medical team continues to believe that existing vaccines will provide some level of protection against severe illness from Omicron, and individuals who have gotten boosters have even stronger protection. As such, we urge all adults to get their booster shots and to get themselves and their kids vaccinated, if they haven't already," Zients said.

Before the virus was detected in the U.S., President Joe Biden also imposed a travel ban on people coming from South Africa. Omicron has been found in dozens of countries around the world, prompting other nations to close their borders and issue pleas for vaccination.

"At least 23 countries from five of six WHO regions have now reported cases of omicron and we expect that number to grow," WHO Director-General Tedros Adhanom Ghebreyesus said this week.

"WHO takes this development extremely seriously and so should every country. But it should not surprise us," Tedros continued. "This is what viruses do. And it's what this virus will continue to do, as we long as we allow it to continue spreading."

COVID outbreak Omicron
At least five people in Northern California have contracted the Omicron variant after attending a wedding in Wisconsin. Here, a new rapid COVID-19 testing site for travelers is seen at Los Angeles International Airport (LAX) on December 3, 2021 in Los Angeles, California, in wake of the new variant. Mario Tama//Getty Images