The outbreak comes as Robert F Kennedy Jr begins his tenure as US health secretary, a role that grants him significant authority over immunisation policy.
Kennedy, a vocal vaccine skeptic, has repeatedly and falsely linked the measles, mumps and rubella (MMR) vaccine to autism, a claim widely debunked by scientific research.
At least 77 of the cases in Texas involve children, while 10 are adults, with data unavailable for the remaining three.
Sixteen patients have been hospitalised with the highly contagious disease, which is best known for its rash but can also cause pneumonia, brain swelling and other severe complications.
Only five of the cases have been reported among vaccinated individuals. The majority of patients were unvaccinated, or their vaccination status remains unknown.
Infants are not eligible for their first dose of the MMR vaccine until 12 to 15 months of age, leaving them vulnerable in early life. People with immune-compromising conditions are also at higher risk of severe illness.
Childhood vaccination rates have been declining across the US, a trend that accelerated during the Covid-19 pandemic amid concerns over the rapid deployment of mRNA vaccines and widespread misinformation, further eroding public trust in health institutions.
The outbreak epicentre is Gaines County in west-central Texas, which has reported 57 confirmed cases.
Texas law allows vaccine exemptions for reasons of conscience, including religious beliefs. The county is home to a significant Mennonite community, a Christian sect that has historically shown vaccine hesitancy.
In 2023, the US reported 285 measles cases, according to the Centers for Disease Control and Prevention (CDC). The worst recent outbreak occurred in 2019, when 1,274 cases – mostly within Orthodox Jewish communities in New York and New Jersey – resulted in the highest national total in decades.
Before the measles vaccine was introduced in 1963, the disease infected an estimated three to four million Americans annually, according to the CDC.
While measles was declared eliminated in the US in 2000, outbreaks continue to occur each year. Globally, the disease remains a major killer, claiming tens of thousands of lives annually.
Meanwhile, the Trump administration has postponed a routine meeting of an independent advisory panel that makes vaccine recommendations to the CDC.
The meeting, originally set for Feb 26-28, was scheduled to discuss vaccines for meningococcal disease, influenza and chikungunya, a viral disease that causes fever and joint pain.
The CDC website now states that the meeting was postponed to “accommodate public comment in advance of the meeting,” but no new date has been announced.