Fans who attended a Portland Trail Blazers NBA game in Oregon earlier this month may have been exposed to measles by a sick attendee, NBC News reports. Officials in Multnomah County, Oregon said an individual “known to be contagious with the disease” attended the game on Jan. 11 and may have exposed other attendees to the viral infection if they were at Portland's Moda Center between 5:30 p.m. and 11:30 p.m. The announcement from Multnomah County comes as officials in nearby Clark County, Washington said there have been 23 confirmed cases of measles since Jan. 1. The majority of the cases in Clark County reportedly affect those between the ages of 1 and 10, and one case resulted in a hospitalization. According to NBC, there have been no confirmed cases in Oregon yet. Measles is highly infectious and will infect 90 percent of those who breathe in the virus and are not immunized. However, the measles vaccine reportedly provides over 95 percent protection against such an infection.