An increase in early measles vaccination may have ultimately curbed cases during the 2025 outbreak in Texas, based on an analysis of data from more than 80,000 children.

In August 2025, the Texas Department of State Health Services announced the end of the 2025 measles outbreak.

In March 2025, the CDC recommended an early measles, mumps, and rubella (MMR) dose (between 6 and 11 months of age) for infants living in or traveling to outbreak areas, said lead author Brianna Cartwright, MS, principal research analyst at Truveta, in an interview.

However, few data were available to understand whether parents and clinicians were adhering to those recommendations, Cartwright said. Cartwright and colleagues at Truveta, a healthcare data and analytics company, identified infants residing in Texas who had outpatient encounters at age 2-4 months, 4-6 months, and 6-11 months between 2019 and April 2025. These encounters were defined as regular, well-child care.

In the study, published as a research letter in JAMA Network Open, the researchers identified MMR or MMR- varicella vaccines administered to children between 182 days and 24 months of age. For each calendar month, they conducted two analyses: the proportion of measles vaccines given early (age, 6-11 months) and the proportion of children who were vaccinated based on age in months (age, 6-11 months) between January 2024 and April 2025. The current recommendation for a first measles vaccination is age 12-15 months.

The study population included 82,949 children (48.6% girls); 63.8% were White, 30.2% were Hispanic or Latino, 12.5% were Black, and 4.3% were Asian individuals.

Among children younger than 2 years and receiving regular care, 1 in 5 received an early vaccine in March and April 2025 (after the CDC recommendation), representing an 11.5-fold increase compared with that in 2019 (the year of the most recent significant measles outbreak), Cartwright said.

In addition, all aged from 6 to 11 months had increased early vaccination rates in March and April 2025, compared with the previous year, Cartwright told Medscape Medical News.

Vaccination rates increased across all age groups during the study period, but children with recommended regular care visits at age 6 and 9 months in March and April showed the greatest increase, indicating that regular care visits may have been a useful point of intervention, Cartwright noted. “Although the 11-month- and 8-month-olds did not have regularly recommended well-child visits in March and April 2025, they also showed increases in vaccination rates, indicating that parents potentially brought their children in for an additional vaccination visit after the guidelines to vaccinate early were released,” she said.

“Our findings highlight the critical role clinicians play in responding quickly to public health guidance during outbreaks,” Cartwright told Medscape Medical News. “Routine well-child visits likely provided valuable opportunities to implement early vaccination recommendations, demonstrating how established care patterns can be used to rapidly increase community protection,” she said.

The findings were limited by the inclusion only of children with healthcare visits in a Truveta member health system, so not all infants were captured in the study, Cartwright said. Also, the study was conducted at the state level, and the researchers did not break out trends by county, she noted.

However, the study underscores the important role clinicians play in communicating with parents in real time, and also how maintaining regular preventive care schedules can promote timely vaccine uptake during a public health crisis, said Cartwright. More research is needed to continue to explore the impact of the outbreak on vaccination trends in affected areas and across the country, she said.

Think Outside the Well-Child Visit

The current study highlights the importance of being able to scale up and accommodate early vaccination during outbreaks or other public health emergencies, wrote Lece V. Webb, MD, of The University of Alabama at Birmingham, and Sean T. O’Leary, MD, of the University of Anschutz Medical Campus, Aurora, Colorado, in an accompanying editorial. “Despite challenges from mis- and dis-information, vaccine refusal, and uneven access, families and clinicians mobilized quickly when faced with the threat of measles,” they said. The rapid uptake likely contributed to the reduced spread of illness by May 2025.

However, the findings also highlight the need to improve vaccine access and delivery for children not scheduled for routine well-child visits, the editorialists wrote. The focus on children with regular healthcare visits may have resulted in overestimation of early vaccination in the Texas population at large, they said.

“Without targeted outreach, such as mobile vaccination units, school- or church-associated vaccination clinics, or other community partnerships, outbreak-driven early vaccination may widen disparities rather than close them,” they noted.

Vaccine Uptake May Reflect Larger Concerns

Shifting measles vaccination down to infants 6 months of age is reasonable during an outbreak such as the 2025 Texas outbreak, said Paul A. Offit, MD, in an interview.

For children already scheduled for well visits, the motivation may coincide with the opportunity on the part of both providers and caregivers, said Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia, Philadelphia, and a professor of pediatrics at the University of Pennsylvania School of Medicine, Philadelphia.

“You’re there in the office anyway, and you’re scared [by the outbreak],” he said. Also, the current political climate may be prompting more families to take advantage of vaccines in general, out of concerns that vaccines may become less available for their children, Offit said.

In the Texas measles outbreak, the uptick in vaccination in March and April likely had no significant impact on the trajectory of the disease, which typically peaks in winter or early spring and recedes in the summer, Offit noted. Looking ahead, early vaccination has value in outbreak situations, but more work is needed to reach families who may not be presenting for routine care, Offit added.

This study received no outside funding, and was created by independent researchers at Truveta, who disclosed no financial conflicts of interest. The editorial authors disclosed no financial conflicts of interest. Offit disclosed no relevant financial conflicts of interest.