Stanford Experts Address Measles Risks Amid Rising National Cases

As the United States grapples with the highest number of measles cases in decades, Stanford University health experts have expressed cautious optimism regarding the potential for a widespread outbreak on campus. As of February 26, 2025, the nation has reported 1,136 confirmed cases of measles, with clusters emerging in California, but Stanford officials assert that the university is currently not at significant risk.

California’s Measles Landscape

In January, California reported 14 measles cases across six counties, including Napa and San Mateo, all linked to a single traveler. The situation escalated in February with an additional 12 cases in Shasta and Santa Clara counties. Despite these incidents, officials including Hayley Gans, a clinical professor of pediatrics and infectious diseases at Stanford, clarified that there is no evidence of sustained community spread within the Bay Area.

“So far, these cases have not represented sustained community spread of a single domestic strain,” Gans stated. She added that if a single strain circulates within the country for more than a year, it could jeopardize the U.S.’s elimination status for measles, a scenario described by Gans as having a “high risk” of occurring.

Understanding Measles Transmission and Immunization

According to Yvonne Maldonado, a professor of global health and infectious diseases at Stanford, measles is considered “probably the most infectious disease that we know of in humans.” The virus spreads through tiny airborne droplets that can remain in the air for up to two hours after an infected person has left a room. This high level of transmissibility—about five times that of COVID-19—means that a community needs approximately 95% immunity to prevent outbreaks.

“One dose of the measles vaccine provides about 95% protection, while a second dose increases that to approximately 97%,” Maldonado explained. She noted that the majority of recent U.S. cases involve individuals who were unvaccinated. “Over 95% of the cases that we’ve seen so far in the U.S. are people who just didn’t get vaccinated,” she added.

At Stanford, students are required to provide vaccination documentation, ensuring a robust defense against measles. Robyn S. Tepper, Medical Director at Vaden Health Center, emphasized the importance of vaccinations, stating that any breakthrough cases among vaccinated individuals are typically mild. She encourages students to ensure their family members are also vaccinated and to stay current with routine immunizations.

Tepper also advised students traveling internationally to consult a travel clinic, as additional vaccines may be necessary. “Stanford is not going to be isolated because of the global nature… with people leaving and coming onto campus or visitors arriving,” Gans noted, highlighting the university’s status as a popular destination.

In light of the current situation, both Gans and Tepper reinforced the importance of preventive measures, stating, “The vaccine is really our only way of protecting people.” They plan to continue monitoring public health alerts to safeguard the Stanford community.

As the situation evolves, the emphasis on vaccination and community immunity remains critical in preventing a resurgence of measles in the U.S. and ensuring the health and safety of the Stanford campus.