Measles Comeback: Why Misinformation Threatens Hard-Won Progress

Measles, once thought to be nearly eliminated in the US, remains a persistent concern for infection preventionists (IPs) and public health officials. In a recent conversation with Infection Control Today^®, Editorial Advisory Board member Matthew Pullen, MD, discussed the dangers of waning vaccination rates and the spread of misinformation.

“We have had cases here [in Minnesota], none that I’ve seen personally,” Pullen said. “A lot of it happens in the pediatric population. It does concern me, though, because measles—like every immunizable disease—relies on herd immunity. And for measles, that threshold is quite high, in the '90s. It doesn’t take much for that herd immunity to start breaking down.”

The Minnesota Department of Health put out a news release yesterday, “New measles cases lead state health officials to issue reminders about immunization, travel, and symptoms,” that said there have been 10 new measles cases this week for a total [of] 18 cases so far in 2025.” The news release said, “These new measles cases can all be tied to either domestic or international travel, and all of the new cases are among unvaccinated people. Health officials are urging families to make sure they are up to date on their immunizations, especially ahead of travel.” One child has been hospitalized.

Arizona is also experiencing a significant and expanding outbreak that has affected the region adjacent to southwestern Utah. There have been 59 confirmed cases in Arizona, including 1 hospitalization. Most of these cases are concentrated in Mohave County, which is in the far northwestern part of the state, bordering Utah.

Pullen explains that beyond its immediate health risks, measles can have long-lasting consequences. He explained the concept of “immunologic amnesia,” a phenomenon where measles infection destroys immune memory cells. “You can end up losing immunity to something that you’d already been exposed to or already had an infection with. By introducing the measles vaccine, we’re not only preventing death and disability from measles, we’re preventing those children who would have been infected from being vulnerable and dying from other infections as well.”

Despite clear evidence of the vaccine’s effectiveness, misinformation continues to challenge public health efforts. Pullen recalled past targeting of Minnesota’s Somali immigrant community by antivaccine groups, which led to significant drops in vaccination. “They were already in quite a vulnerable position… and this antivaccine group was specifically targeting them with literature in their language, saying the vaccine will sterilize your children or harm your children,” he said. “From my understanding, [vaccination rates] are now kind of recovering, but there are challenges.”

Pullen emphasized that vaccine misinformation comes from a mix of misunderstanding and deliberate disinformation. The Vaccine Adverse Event Reporting System (VAERS), he noted, is often misused. “Just because something was reported doesn’t mean that it is a vaccine adverse effect. Most of those are noise,” he explained. “When you do the risk-benefit analysis, it always falls in favor of vaccinating.”

From cultural targeting to conspiracy-driven narratives, Pullen said the stakes are high. “When your stance is irrational and it’s not backed by medicine and it’s hurting people, that’s really, really dangerous.”