As the United States experiences its highest number of measles cases in decades, Stanford University officials are cautiously optimistic about the situation on campus. As of February 26, 2025, there have been **1,136 confirmed cases** nationwide, marking a significant increase in incidents since the disease was declared eliminated in 2000.
In January, **14 cases** were reported across six counties in California, including **Napa** and **San Mateo**, all linked to a single traveler. February saw **12 additional cases** in **Shasta** and **Santa Clara** counties. Despite these clusters, Stanford health experts assert that there is currently no widespread outbreak in the Bay Area.
Hayley Gans, a clinical professor of pediatrics and infectious diseases at Stanford, stated, “So far, these cases have not represented sustained community spread of a single domestic strain.” However, she warned that should a single strain circulate within the country for over 12 months, the U.S. could risk losing its elimination status. Gans described this scenario as having a “high risk” of occurring.
Measles is considered one of the most infectious diseases known to humans. Dr. Yvonne Maldonado, a professor of global health and infectious diseases, explained that the virus spreads through tiny airborne droplets, which can remain in the air for up to two hours after an infected person has left the room. The transmission rate of measles is significantly higher than that of COVID-19, requiring high levels of community immunity to prevent outbreaks.
According to Maldonado, “You need about **95%** of people in a community to be immune to prevent an outbreak.” A single dose of the measles vaccine offers roughly **95% protection**, while two doses increase immunity to around **97%**.
While California has reported cases in several counties, Maldonado emphasized that this does not indicate a widespread outbreak in the Bay Area. In epidemiological terms, an outbreak is defined as three or more related cases of a disease. She noted that over **95%** of the cases observed in the U.S. have involved individuals who were unvaccinated.
Stanford students are required to be vaccinated against measles, with the two-dose vaccine providing substantial protection. Dr. Robyn S. Tepper, Medical Director of Vaden Health Center, stated, “Any breakthrough cases are typically mild.” Tepper explained that requiring students to provide vaccine documentation prior to enrollment helps protect the Stanford community.
Tepper also advised students to ensure their family members are vaccinated and to stay current on routine immunizations. For those planning to travel internationally, consulting a travel clinic is recommended, as additional vaccines may be necessary.
Gans noted that Stanford’s global nature, with many visitors coming to campus, increases the potential for exposure. “We remain committed to supporting a healthy campus and will continue to monitor public health alerts,” Tepper added.
Experts emphasize that vaccination is the most effective means of preventing measles outbreaks. Gans highlighted the vital role of the vaccine in safeguarding public health, stating, “The vaccine is really our only way of protecting people.”
By prioritizing vaccination and remaining vigilant, the Stanford community aims to mitigate the risks associated with the ongoing rise in measles cases nationwide.
