Los Angeles health officials have announced that over 300 students and staff at UCLA and Cal State Los Angeles who have been exposed to measles will be quarantined for at least a day, the Los Angeles Times reports. A UCLA student may have exposed up to 500 people to measles while going to class earlier this month, and 127 of those at-risk have yet to provide medial records proving their immunity to measles. An individual visiting Cal State LA's library also was infected with measles earlier this month, and may have exposed hundreds to the disease. One hundred ninety-eight people potentially exposed at Cal State LA did not provide immunization records, prompting public health officials to move to quarantine 325 people for 24 to 48 hours. The individuals will be quarantined until proof of immunity can be established, and some may be quarantined for up to a week. This comes after the state confirmed 15 new cases of measles were diagnosed since last week. There are currently almost 700 cases of measles nationwide, the most in the U.S. since 2000.