So-called breakthrough cases in vaccinated measles patients are not unprecedented, according to Dr. Sarah Rudman, Santa Clara County\u2019s health officer.<\/p>\n
Rudman said that when \u201cthere\u2019s this much measles spreading around, both around the country and internationally,\u201d vaccinated people can still be infected, although it\u2019s less common. Rudman clarified that the majority of cases still occur in unvaccinated people.<\/p>\n
Rudman also echoed the CDC\u2019s guidance<\/a> that measles cases in vaccinated people tend to be less severe than in unvaccinated people. People with two MMR vaccine doses are likely to only be \u201cmoderately sick,\u201d she said, and recovering \u201cfaster and are less infectious, which means the disease spreads less.\u201d<\/p>\n \u201cThat\u2019s one more reason why it\u2019s so important for the community to have high rates of immunity against measles by being up to date on vaccination,\u201d she said.<\/p>\n What if you have two vaccine doses but are now worried about being infected with measles? Rudman said that for most people who have a record of their vaccination or a childhood case of measles, \u201cit\u2019s not necessary to go check your measles immunity status<\/a>.\u201d<\/p>\n However, Rudman said, for those who are vulnerable due to their medical history, an upcoming travel plan or medical treatment, \u201cit might make sense to talk to your doctor and check your immune status.\u201d She said this can be done by verifying vaccination records or by a blood test for proof of immunity.<\/p>\n Read more about how titer tests can assess your immunity<\/a> against measles, and how to ask your provider about getting one.<\/p>\n What\u2019s going on with measles in 2026?<\/p>\n The Santa Clara case marks the 22nd<\/a> measles case in California in 2026, with the county\u2019s first confirmed measles case in a resident since May 2025. It\u2019s believed to be the Bay Area\u2019s fourth measles case in 2026, with previous cases reported by San Mateo and Napa counties.<\/a><\/p>\n According to the Centers for Disease Control and Prevention\u2019s most recent data<\/a>, 1,136 cases of the highly contagious disease have already been reported around the United States this year \u2014 with the majority of cases fueled by an outbreak in South Carolina. Last year saw a total of 2,144 confirmed cases,<\/a> in contrast to just 285 cases in 2024.<\/p>\n