Several South Korean companies were in attendance at the show, including Samsung, Hyundai and SK. South Korean officials did not break down the caseload by company, but Hyundai officials tell CNN six of its employees tested positive before leaving the show, and have been quarantined in their hotels in Las Vegas since then.  (Two have recently tested negative and are finally on their way home.)

“Many people who attended the CES international electronic product fair in Las Vegas, US, last week are testing positive for COVID-19,” said Son Young-rae, a South Korean senior health official, in a health briefing Wednesday. “We are promptly contacting them and conducting an epidemiological investigation for those who participated in the event, but we urge business people who attended this event … to receive a PCR test as soon as possible.”

The decision to hold an in-person version of CES on Jan. 5-7 wasn’t without controversy. As Omicron cases exploded, many big companies, including Google, Amazon, Meta, T-Mobile and Intel, pulled out of the show, as did many media companies. And many feared the event could be a breeding ground for COVID to spread.

In the end, though, the show reported attendance of over 40,000 people in person, with 30% of those attendees traveling from outside the U.S. Attendees were required to be vaccinated and the show had a mask requirement, though there were many photos posted during the show where people were unmasked.

It is, of course, impossible to say exactly whether the people were infected on the show floor or in some other part of Las Vegas, such as casinos, where mask wearing is much less common. However, the surge in South Korean cases does raise concerns for others who attended the show and how many of them left Las Vegas as a possible carrier.