The US has surpassed 2,000 confirmed measles cases in 2023, nearing the total of 2,228 from all of 2025, indicating a potential worst year for measles in decades. The outbreak is fueled by low vaccination rates and misinformation.
Key points
US records over 2,000 confirmed measles cases in 2023
Potentially worst year for measles in decades
Outbreak driven by low vaccination rates and misinformation
Virginia and Pennsylvania seeing rising cases
Utah's outbreak shows different spread patterns
The US has recorded more than 2,000 confirmed measles cases so far this year – near the total of 2,228 recorded in all of 2025, and on track to become the worst year for measles in decades as states struggle with the loss of federal funding for public health.
The virus continues to spread in unvaccinated and under-vaccinated communities, including among babies too young to be vaccinated, and it reveals the depths of the twin crises of misinformation and public health in the US.
The US recorded 2,030 cases on 4 June, though experts believe the true number is about three times higher. Cases in Utah appear to be winding down, while cases in Virginia and Pennsylvania appear to be picking up.
“I think it’s going to be a busy summer,” said Andrew Pavia, a George and Esther presidential professor who spoke in his personal capacity as an infectious disease expert.
Utah has shown a new side of the outbreak. “What makes Utah different than South Carolina and Texas is that it spread throughout the entire state and became much more widely distributed,” Pavia said.
Even so, there were two factors that made a difference in whether cases were contained, Pavia noted: “It hit hardest in communities that had relatively low vaccination rates and relatively limited public health departments.”
While the Utah cluster began in a community with low connections to public health, making it hard to track cases, it quickly spread elsewhere. “With immunization rates having fallen off for 15 to 20 years in some places, there are young adults who are susceptible, who grew up in otherwise typical middle-class settings,” Pavia said.
Controlling measles also requires strong public health: vigorous contact tracing, isolation for the sick, and quarantine for the exposed – an increasingly politicized task following the Covid pandemic. Utah has a decentralized public health system, so most of the response came from local public health departments.
“Some of these small health departments are very stressed for personnel, funds, and training, particularly after the massive cuts that the administration made to pass-through money that went to state and local health departments – I think it was $11 billion they took away,” Pavia said.
The governor of Utah, Spencer Cox, “has not uttered the word ‘measles’ since 2024”, and the health department had to clear all of its announcements through political leadership, making it less visible and less vocal than other states, Pavia said. He contrasted the approach in South Carolina, where the governor and director of the health department gave regular updates and “spoke with one voice about the need for containment”, he said.
Q&A
How many measles cases have been reported in the US in 2023?
The US has reported over 2,000 confirmed measles cases so far in 2023.
What factors are contributing to the measles outbreak in the US?
The outbreak is primarily driven by unvaccinated and under-vaccinated communities, as well as misinformation about vaccines.
Which states are currently experiencing a rise in measles cases?
Virginia and Pennsylvania are seeing an increase in measles cases, while cases in Utah appear to be declining.
What is the significance of the measles outbreak in 2023 compared to previous years?
The outbreak in 2023 is on track to become the worst year for measles in decades, with current cases nearing the total recorded in 2025.
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The measles outbreak is officially contained in South Carolina, and there was a 162% jump in vaccinations in Spartanburg county in January. But that response was still challenging, said Annie Andrews, a pediatrician in South Carolina. Before the outbreak ended, it climbed to nearly 1,000 documented cases – probably 2,000 to 3,000 cases in actuality – with at least one young boy hospitalized with measles encephalitis.
Watching it unfold was “incredibly frustrating”, Andrews said. “None of this had to happen. This was entirely preventable, and this is a direct result of decades’ worth of vaccine misinformation and disinformation.”
In early 2025, US poison control centers reported a 38.7% increase in exposures to vitamin A, while internet searches surged for the unproven treatment, touted by Robert F Kennedy Jr, the secretary of the US Department of Health and Human Services (HHS) and a longtime vaccine critic, according to a new analysis. Kennedy has also framed measles vaccination as a personal choice as the outbreak continues to spiral through the US.
High levels of vaccination can keep outbreaks from growing, and they can also protect those who can’t get vaccinated or don’t respond to vaccines. Babies under one year of age aren’t usually vaccinated, and they can’t get the shots before six months of age – making them particularly vulnerable during outbreaks. In Texas, a baby born to a measles-positive mother had to be hospitalized with acute measles meningoencephalitis, according to a new report published by the US Centers for Disease Control and Prevention (CDC) in the Morbidity and Mortality Weekly Report (MMWR).
When Pavia was a child, every parent was terrified when measles swept through the community.
“Everyone knew a child who had a bad outcome from measles, and they didn’t take measles for granted. That’s no longer true,” Pavia said.
Now, when cases flare and patients report even with uncomplicated symptoms – intense light sensitivity, painful diarrhea, high fevers – he and his colleagues hear the same thing again and again: “This was worse than anybody told me it was going to be.” Parents say they’ve never seen their kids so sick.
“We are nowhere out of the woods from this anti-science era we find ourselves in here in South Carolina and in other places across the country, and that environment just made us really vulnerable to this measles outbreak,” Andrews said. “RFK Jr has been one of the figures leading that spread of disinformation.”
Misinformation from top health leaders has made it more difficult to combat the outbreak on the ground, Pavia said. “When you have the situation we have now with the secretary of HHS, who is a longstanding vaccine critic, who did not do anything proactive nationally to help change the attitudes towards measles – you’re dependent on local officials standing up, and that’s been variable.”
Andrews has known she wanted to be a doctor since she was four years old, and she knew she wanted to be a pediatrician from the first time she set foot in a children’s hospital more than 20 years ago. But now, she finds herself taking on new roles she never imagined: she’s become a social media influencer, explaining why vaccination is so important and taking on common misconceptions about health.
“Pediatricians and other physicians created a vacuum in social media spaces that allowed RFK Jr and other anti-science, anti-vaccine influencers to fill that void,” Andrews said. “I think pediatricians and physicians just never understood the importance of engaging in those spaces. That’s where real people are, that’s where our patients are getting their information, and because we didn’t engage there, the disinformation took over, and it’s going to take us so long to claw back at that, to regain the trust.”
Offering information that is accessible and engaging is a key part of being a medical professional, she added. “Until we accept that, we’re going to continue to get outflanked in these spaces and end up right back where we are today.”
Now, Andrews is aiming for an even bigger platform, running for US Senate in South Carolina. If elected, she would be the first woman physician in the Senate, and the first pediatrician senator ever. “There’s never been a more urgent need for scientifically literate, data-driven lawmakers to be in the rooms where these conversations are happening,” she said.
It’s going to take decades to counter the distrust that permeates the public health and medical systems in the US, she said. “It’s so pervasive now, this distrust in vaccines, this misunderstanding of the safety and efficacy of vaccines,” Andrews said. “It’s so heartbreaking to watch patients suffer as a result.”
