As Measles Cases Hit Record 35-Year Highs In The US, We Ask An Expert: What Can Be Done To Combat Re-Emerging Diseases?

• The US has officially recorded over 2,300 measles cases so far in 2026 – more than in the whole of 2025.
• Cases are also at their highest level for 35 years. 
• Vaccine hesitancy is a big reason why; but as Stanford University assistant professor Nathan Lo told IFLScience, “It’s important to adapt our vaccine policy and interventions to address the threat of measles re-emergence.”

The US has now officially recorded more measles cases in 2026 than were seen in the whole of 2025 – and we’re only seven months into this year. 

The Centers for Disease Control and Prevention (CDC) confirmed as of July 23 that 2,302 measles cases had been reported across 45 jurisdictions, and 16 in visitors coming to the United States from overseas.

Of these 2,318 total cases, 93 percent are associated with outbreaks, most of them outbreaks that actually started last year.

During the full, record-breaking year of 2025, 2,289 confirmed measles cases were recorded in the country. 

Not only have we already surpassed this total in 2026, but cases have now reached a reported 35-year high. Remember, this is a vaccine-preventable disease. What are we even doing?

The “post-elimination era” dawns

The US, like many other countries, once considered measles eliminated from its shores. Now, like several of those countries already have – including the UK and Canada – it looks set to be stripped of this official elimination status.

“In terms of infectious diseases that we have eliminated from the US through widespread vaccination, measles is at the greatest risk of re-emergence,” Dr Nathan Lo, an Assistant Professor of Infectious Diseases at Stanford University, told IFLScience.

A big reason for this is that measles is highly contagious – even more so than nightmare diseases like smallpox. 

An estimated nine out of 10 unvaccinated people exposed to the virus will develop symptoms. Infectious particles can linger in the air for an hour or more after someone with the disease has left a room.

That means that a small number of cases can quickly become an outbreak. It’s a headache for healthcare facilities treating people sick with measles, as infection control is incredibly challenging. And it means that only a small decrease in vaccine coverage is enough to let the virus surge forth.

Vaccine science under attack

The measles vaccine is arguably among the greatest innovations medicine has ever produced. The CDC explains that before widespread vaccination in the US, nearly all children contracted the disease before the age of 15.

This led to approximately 400-500 deaths, 48,000 hospitalizations, and 1,000 cases of encephalitis – dangerous inflammation of the brain – every single year. 

That changed drastically once a single measles vaccine, then later the MMR, was developed. The MMR not only protects against measles, but two other major childhood diseases: mumps and rubella. More recently, it’s been updated even further to include chicken pox (varicella), in what’s known as the MMRV vaccine. 

The MMR and MMRV are both safe, effective vaccines that have been extensively studied. Two doses are about 96 percent effective against measles, 86 percent against mumps, 89 percent against rubella, and 97 percent against chicken pox. 

But the MMR has also been the target of a huge amount of antivax mis- and disinformation. 

The infamous 1998 study led by Andrew Wakefield and published in The Lancet medical journal kickstarted a misinformation machine that has whirred on ever since. Wakefield used it to claim a link between childhood vaccinations and autism – a claim that has never been substantiated, despite the large number of studies that have since investigated it.

The paper was eviscerated by other experts in the field and eventually retracted, but the damage to the public image of the MMR vaccine had already been done, especially in Wakefield’s native UK. It took years to bring immunization levels back up to where they had been before. 

Wakefield was prevented from practicing medicine again, but that didn’t stop the antivax train. Worse still, this cause has now been taken up by figures at the very top of the US federal government. 

Robert F. Kennedy, Jr, who has been Health and Human Services Secretary under the Trump Administration since February 2025, has publicly expressed antivax views on numerous occasions. 

Almost immediately after he assumed office, the administration announced funding for a study into the debunked link between vaccines and autism. In May 2025, he incorrectly stated that the MMR vaccine contains “a lot of aborted fetus debris and DNA particles”. 

Kennedy publicly called for a journal to retract a study that found no link between aluminum in vaccines and chronic health problems, claiming it was “deceitful propaganda” and had “fatal deficiencies”. 

On measles specifically, he's touted unproven “cures” that risk real harm when not used under medical supervision.

He also pronounced that all new vaccines developed during his tenure would need to be tested in placebo-controlled trials, despite the well-established ethical and practical reasons why that is not done.

Recent leaked emails show the true extent of Kennedy’s ongoing war on US vaccine policy. But it goes even further up the chain than him. 

President Trump himself made comments that were endorsed by then acting director of the CDC Jim O’Neill, questioning why the MMR vaccine could not be split up into three separate shots – a suggestion straight out of the Wakefield playbook.

The reason, incidentally, is simple: giving the vaccines together is not associated with any health risks and limits the window of time in which children are still exposed to catching each disease. 

The apotheosis of all this, perhaps, is the fact that the official website of the CDC, the leading public health agency in the United States, was quietly updated last year with the statement “the claim ‘vaccines do not cause autism’ is not an evidence-based claim”.

This is not true.

“The first step is listening and learning about an individual’s concern” 

Given the constant attacks being levelled at vaccination as a technology - and the MMR vaccine specifically - it’s unsurprising that vaccine coverage has dropped in some regions of the US.

Winning back people’s trust in the vaccine, especially when their leaders are some of the loudest voices in opposition, is an extremely difficult task – but the majority of public health experts agree that it’s the best option available for tackling measles.

“As a physician, the first step is listening and learning about an individual’s concern, and sharing information to address those concerns,” Lo told IFLScience. “On a population-level, strategies should similarly be tailored to address the particular context.”

“It’s important to adapt our vaccine policy and interventions to address the threat of measles re-emergence.”

Generally a small fraction of the US is at greatest risk for sustained outbreaks.

Dr Nathan Lo

Lo co-authored a paper recently with Stanford PhD student Chirag Kumar which addressed this problem.

One issue they raise is that interventions should be targeted to specific regions – not everywhere in the US is at the same risk of seeing a measles outbreak.

“Risk of measles is generally quite concentrated in certain locations that have a confluence of factors, such as low vaccination rates, high travel (leading to risk of an introduced case of measles), and other factors that facilitate disease spread,” Lo told us.

“This means that generally a small fraction of the US is at greatest risk for sustained outbreaks.”

Kumar and Lo also reiterate the importance of listening to individuals’ concerns about vaccines, as well as engagement efforts at a population level that “focus on genuinely addressing concerns while simultaneously articulating the positive impact of vaccines to reduce illness and long-term complications, along with the safety of vaccines.”

It’s difficult work, but it has to be done – and it’s not too late.

We’ve already seen moves within the United States to offer an alternative to the views being put forward by the federal government.

Self-organizing support

The states of California, Hawaii, Oregon, and Washington formed the West Coast Health Alliance in response to what they called “the Trump Administration’s destruction of the US CDC’s credibility and scientific integrity.”

Experts also came together to form the Vaccine Integrity Project, in an effort to provide “trusted, science-based information for informed vaccine choices”.

And earlier this year, the American Academy of Pediatrics released its own childhood vaccine recommendations after changes to the CDC schedule saw the list of diseases covered dropping from 18 to 11.

“Whether the current re-emergence of vaccine-preventable diseases represents a temporary setback or the beginning of a broader transition remains to be seen, but even the existing trajectory represents a significant loss to decades of global health progress,” Kumar and Lo write.

“In an era where public health is increasingly politicised, continued investment and support for public health infrastructure is ultimately about preventing illness and saving lives. As the threat of re-emergence of vaccine-preventable diseases grows, much work remains to be done to sustain the value of vaccines worldwide.”

The paper is published in PLOS Medicine.