ABC7 News reporter Leslie Brinkley spoke with an epidemiologist who attended the wedding and got sick herself.
RELATED: California omicron cases linked to Wisconsin wedding, health officials say
Debra Furr-Holden is the associate Dean of Public Health Integration at Michigan State University.
"I'll give people a cautionary tale," she said. "If a group of medical professionals and public health professionals can't prevent spread at a social gathering, it's just the luck of the draw for everybody."
She said she attended the November 27 wedding in Wisconsin where there were about 100 guests, who were masked at the church and reception except while eating, drinking or dancing.
She recalls, "Thinking I was at an event with very responsible people who are very smart. We all did the right thing, we got tested in advance. We got our vaccines. Many had boosters. And we still ended up infecting each other and then some of us came home and infected our loved ones."
RELATED: COVID-19 outbreak at Wisconsin wedding infects 11 Oakland Kaiser workers
Furr- Holden infected her daughter and had to isolate from her three month old granddaughter. She said she got a scratchy throat and severe headache but is ok now.
Kaiser Permanente said Alameda Public Health announced 12 COVID-19 cases on December 3, many of them the omicron variant.
11 of those cases are among staff at Kaiser's Oakland Medical Center. One worked at Highland Hospital.
Alameda County Public Health Officer Dr. Nicholas Moss says, "From my understanding all of them had traveled to the wedding."
RELATED: How severe is omicron? Expert says variant's 50 mutations could be its downfall
Ultimately eight patients and eight additional staff at Kaiser were identified as being potentially exposed, but tested negative.
"I think we have to be a bit more vigilant," Furr-Holden said. "We all have COVID fatigue. The virus does not."
The bride and groom left immediately from the wedding on a honeymoon overseas. They tested positive and are still in a 14-day quarantine.