As the calendar turned to 2026, measles continued to spread throughout the US. In 2025, the US confirmed the most measles cases in 34 years. Fueled by areas with low vaccination rates, the virus shows no signs of slowing down. South Carolina – the epicenter of one of the largest outbreaks – saw 124 new infections in the past few days alone, raising the state’s total to 558 cases.
“We have right now the largest outbreak in the U.S., and it’s going to get worse before it gets better,” said Dr. Helmut Albrecht, an infectious disease physician with Prisma Health and the University of South Carolina School of Medicine. “We have lost our ability to contain this with the immunity that we have”.
Like in other states, pockets of low vaccination are driving the outbreaks in South Carolina. The vaccination rate for schoolchildren in South Carolina’s Spartanburg County is 90% overall, below the the 95% level necessary to stop measles from spreading. On an even more local level, some communities have vaccination rates much lower than that; One school has a vaccination rate of 20 percent. These gaps in coverage allow the virus to spread extremely fast, like a raging wildfire. Measles is the most contagious disease known to affect humans.
This is why spotting cases quickly and containing its spread is so critical. There are several key tools we have to prevent and contain outbreaks. One is contact tracing, in which trained public health workers speak with someone who has measles, and warn their close contacts that they were potentially exposed.
Wastewater testing has emerged as another potent weapon to fight infectious diseases. Wastewater testing serves as an early warning system which can reveal cases days or even months before they are diagnosed by physicians. In Colorado, for example, the wastewater monitoring systems helped the health department ramp up containment efforts well in advance of confirmed cases. When properly funded, these systems can work together with contact tracing to stop the virus in its tracks.
