South Carolina's measles outbreak is among the worst in the US, with 99 new cases in the past 3 days bringing the total to 310, mostly in Spartanburg County.[6][5] The outbreak also spread to the states of North Carolina and Ohio with families traveling to the affected area in northwestern South Carolina.[6] Health officials attribute the spike to holiday travel, family gatherings and low vaccination rates in the region.[6] As of Friday, 200 people were in quarantine and 9 in isolation, while hundreds of schoolchildren had to be repeatedly excluded from schools because of the quarantine.[6] South Carolina is one of two current measles outbreaks in the US, the other being on the Arizona-Utah border, which has seen 337 cases since August.[6] Across the United States, there were 2,144 confirmed cases of measles in 44 states last year, the most since 1991.[6]