ARI SHAPIRO, HOST:
Health officials are scrambling as the measles outbreak continues to spread. According to the Centers for Disease Control and Prevention, this is the worst outbreak of the virus since it was eradicated in the U.S. almost 20 years ago. In Los Angeles, health officials say more than 650 people may have been exposed to the virus at two universities. NPR's Nathan Rott has more.
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NATHAN ROTT, BYLINE: At the University of California, Los Angeles, better known as UCLA, there is little outward indication that a health scare is even going on. Middle school groups are still touring its campus.
ROTT: Students are still ambling between classes, eyes glued to smartphones. But just about everyone here seems to know about the measles scare and that a student who had the virus attended classes at two buildings here earlier this month even if they're not all that concerned.
ANNIE CUI: Maybe I should be but, (laughter) I have other things to worry about.
SAM SUMAN: I know that it's freaking some people out, but I'm not personally worried about it.
RILEY WILSON: My mom texted me and said, you know, Purell your hands. Do you have this mask or whatever? And if I'm going to be honest, I'm not going to take those extra precautions (laughter) simply because I think it's so unlikely.
ROTT: Annie Cui, Sam Suman and Riley Wilson say they have all been vaccinated. And although they're not overly concerned, campus officials and health professionals are. The Los Angeles County Department of Public Health has moved to quarantine more than 650 students and faculty members at UCLA and Cal State, Los Angeles, another university near downtown. Robert Lopez is the spokesman for Cal State, Los Angeles, where most of the exposures may have occurred.
ROBERT LOPEZ: Those are folks who were unable to provide documentation of vaccination or who have not been vaccinated.
ROTT: At UCLA, some students were initially quarantined on campus. The university says only one remains so. Most of those who are being asked to quarantine are being told to just stay at home. At a press conference, Barbara Ferrer, the county's director of public health, said they took that step because measles is so contagious.
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BARBARA FERRER: One person with a confirmed measles case can expose thousands of people.
ROTT: The virus is spread through the air when an infected person coughs or sneezes. It can also be spread if an infected person leaves traces of the virus on something other people touch - say, a door handle or a handrail. That's particularly concerning at places like college campuses.
KAREN SMITH: You have a lot of people in very close contact to one another, and measles is extremely good at spreading in those circumstances.
ROTT: Dr. Karen Smith is the director of the California Department of Public Health. She says that California has a high vaccination rate on the whole at about 95 percent.
SMITH: The challenge is that the unvaccinated population is clustered in particular locations.
ROTT: That's been the problem in outbreaks in other parts of the country, particularly in religious communities that have lower vaccination rates. In 2015, the California university system created a rule requiring students to be fully vaccinated before enrolling at campus, but they did not begin enforcing that regulation until last year. Nathan Rott, NPR News, Los Angeles. Transcript provided by NPR, Copyright NPR.