Measles Outbreak in Texas and New Mexico Sickens Nearly 100 People

Outbreaks of measles in parts of Texas and New Mexico have sickened nearly 100 people, according to state health officials who warned that the number of cases was expected to rise.

An outbreak has been spreading through the South Plains region of Texas since late January, the Texas Department of State Health Services said on Friday. Measles vaccination rates in the region lag significantly below federal targets.

On Friday, the department confirmed 90 cases of measles, with at least 77 of them being children. Sixteen people have been hospitalized, the department said.

The cases come amid growing concerns by public health experts about declining vaccination rates and the confirmation of Robert F. Kennedy Jr., a prominent vaccine skeptic, as the nation’s health secretary.

Mr. Kennedy, who has cited disputed research on the side-effects of vaccines, has vowed to scrutinize childhood vaccines.

In Texas, a majority of the cases have been concentrated in Gaines County, a farming area close to the New Mexico border. In only five of the 90 cases were patients vaccinated against measles. The rest were unvaccinated or had an unknown vaccination status, the department said.

The New Mexico Department of Health said that, as of Thursday, it had identified nine cases of measles in Lea County, which shares a border with the outbreak region in Texas. Four of those infected were children, the department said.

The Texas Department of State Health Services said it was working with local health departments to investigate the outbreak. Local health departments have expanded vaccination clinics and testing hubs to try to stem the cases.

Free walk-in vaccinations were being offered in Seminole in Gaines County, as well as in Lea County, N.M.

Children must receive the measles, mumps and rubella vaccine to attend public schools in Texas, though exemptions can be granted for “reasons of conscience.” But Gaines County had one of the highest exemption rates in the state last year, with more than 13 percent of K-12 students exempted from receiving the vaccine, according to state data.

The vaccination rate in the county for kindergarten students who received the M.M.R. vaccine last year was 82 percent, about 10 points lower than the state average for Texas public schools. The Centers for Disease Control and Prevention has said that when more than 95 percent of people in a community have been vaccinated, most people will be protected through immunity.

Outbreaks of measles, one of the most contagious diseases known to humans, have been emerging in every region of the world. That is also true for the United States, where the disease had once been declared eliminated.

There were 285 total cases in the United States across more than 30 states in 2024, according to the C.D.C.

The disease can severely sicken people or be fatal. About one in five unvaccinated people who become infected with measles ends up hospitalized, the C.D.C. said.

National vaccination rates for measles had already been declining since the Covid-19 pandemic began in 2020, and sat at less than 93 percent last year.