Northern California health officials addressed what they are calling an ongoing local measles outbreak, as cases continue to rise and a pediatric care setting has been exposed to the virus. Sacramento County Public Health Officer Dr. Olivia Kasirye was joined by Dr. Robert Oldham with Placer County Public Health, Dr. Dean Blumberg with UC Davis Health and Dr. John Belko, a pediatric infectious diseases specialist with Kaiser Permanente.At the news conference, Kasirye said the number of cases in Sacramento County rose to 11. Ten of the cases had no vaccination records, she said. Kasirye also said an exposure was confirmed at a pediatric care setting, but she would not say which one.Oldham said the number of cases in Placer County remains at eight, but urged people who are not vaccinated to reconsider group activities.Blumberg stressed how infectious measles is, comparing it to COVID-19. He said that with COVID, four to five people can be infected from one person. With measles, he said about 15 people could be infected by one person.Watch the full news conference belowMeasles is so infectious, Blumberg said, that the infected person does not even have to be in the same room to spread the virus because it can linger in the air for up to two hours after the infected person leaves the room.“That is why we worry so much about it. We worry that there can be more explosive outbreaks. So, every single case we take very, very seriously,” Blumberg said.Both Sacramento and Placer counties plan to continue providing weekly updates on the number of measles cases.As of 12 p.m. Monday, data from the California Department of Public Health show that 39 cases have been confirmed in the state this year so far, but that number is likely to increase with the six additional cases Sacramento County reported at the news conference.Of those 39 cases, 37 people were either unvaccinated or their vaccination status was unknown. Two cases have led to hospitalizations. Measles is an airborne virus and one of the most contagious diseases in the world, especially among children.Health experts say vaccination remains the most effective way to prevent infection. The measles, mumps and rubella vaccine — known as the MMR vaccine — provides more than 99% protection against measles for people who are fully vaccinated.Compared to the 39 cases so far this year, CDPH reported 25 confirmed cases in 2025 and 15 cases in 2024.See more coverage of top California stories here | Download our app | Subscribe to our morning newsletter | Find us on YouTube here and subscribe to our channelPHNjcmlwdCB0eXBlPSJ0ZXh0L2phdmFzY3JpcHQiPiFmdW5jdGlvbigpeyJ1c2Ugc3RyaWN0Ijt3aW5kb3cuYWRkRXZlbnRMaXN0ZW5lcigibWVzc2FnZSIsKGZ1bmN0aW9uKGUpe2lmKHZvaWQgMCE9PWUuZGF0YVsiZGF0YXdyYXBwZXItaGVpZ2h0Il0pe3ZhciB0PWRvY3VtZW50LnF1ZXJ5U2VsZWN0b3JBbGwoImlmcmFtZSIpO2Zvcih2YXIgYSBpbiBlLmRhdGFbImRhdGF3cmFwcGVyLWhlaWdodCJdKWZvcih2YXIgcj0wO3I8dC5sZW5ndGg7cisrKXtpZih0W3JdLmNvbnRlbnRXaW5kb3c9PT1lLnNvdXJjZSl0W3JdLnN0eWxlLmhlaWdodD1lLmRhdGFbImRhdGF3cmFwcGVyLWhlaWdodCJdW2FdKyJweCJ9fX0pKX0oKTs8L3NjcmlwdD4=

SACRAMENTO, Calif. —

Northern California health officials addressed what they are calling an ongoing local measles outbreak, as cases continue to rise and a pediatric care setting has been exposed to the virus.

Sacramento County Public Health Officer Dr. Olivia Kasirye was joined by Dr. Robert Oldham with Placer County Public Health, Dr. Dean Blumberg with UC Davis Health and Dr. John Belko, a pediatric infectious diseases specialist with Kaiser Permanente.

At the news conference, Kasirye said the number of cases in Sacramento County rose to 11. Ten of the cases had no vaccination records, she said. Kasirye also said an exposure was confirmed at a pediatric care setting, but she would not say which one.

Oldham said the number of cases in Placer County remains at eight, but urged people who are not vaccinated to reconsider group activities.

Blumberg stressed how infectious measles is, comparing it to COVID-19. He said that with COVID, four to five people can be infected from one person. With measles, he said about 15 people could be infected by one person.

Watch the full news conference below

Measles is so infectious, Blumberg said, that the infected person does not even have to be in the same room to spread the virus because it can linger in the air for up to two hours after the infected person leaves the room.

“That is why we worry so much about it. We worry that there can be more explosive outbreaks. So, every single case we take very, very seriously,” Blumberg said.

Both Sacramento and Placer counties plan to continue providing weekly updates on the number of measles cases.

As of 12 p.m. Monday, data from the California Department of Public Health show that 39 cases have been confirmed in the state this year so far, but that number is likely to increase with the six additional cases Sacramento County reported at the news conference.

Of those 39 cases, 37 people were either unvaccinated or their vaccination status was unknown. Two cases have led to hospitalizations.

Measles is an airborne virus and one of the most contagious diseases in the world, especially among children.

Health experts say vaccination remains the most effective way to prevent infection. The measles, mumps and rubella vaccine — known as the MMR vaccine — provides more than 99% protection against measles for people who are fully vaccinated.

Compared to the 39 cases so far this year, CDPH reported 25 confirmed cases in 2025 and 15 cases in 2024.

See more coverage of top California stories here | Download our app | Subscribe to our morning newsletter | Find us on YouTube here and subscribe to our channel