The ongoing measles outbreak that began earlier this year in Gaines County, Texas, is continuing to spread rapidly, now reaching neighboring states. The Oklahoma State Department of Health has confirmed four cases linked to the outbreak, marking the latest expansion of the highly contagious disease.

As of March 18, a total of 321 measles cases have been reported across Texas, New Mexico, and Oklahoma. The epicenter remains in Texas, where 279 cases have been confirmed — including at least 208 children and 52 adults — with 36 hospitalizations. The outbreak has now affected 11 Texas counties.

New Mexico has reported 38 cases, involving 17 children and 20 adults, with two individuals hospitalized. Health officials confirmed that all four cases in Oklahoma are connected to exposures linked to the Texas and New Mexico outbreaks.

The majority of infections have occurred in individuals who are either unvaccinated or whose vaccination status remains unknown. Notably, six cases have been reported in individuals who had received at least one dose of the measles-mumps-rubella (MMR) vaccine — two in Texas and four in New Mexico — underscoring the virulence of the outbreak.

Tragically, Texas reported its first measles-related death last month — a school-aged child who was unvaccinated and had no underlying health conditions. Meanwhile, New Mexico health authorities are investigating the death of an unvaccinated individual who had tested positive for measles.

Health experts are warning that the outbreak may continue to escalate, given the disease’s high level of contagion and its spread across rural, multistate regions.

"This is going to be a large outbreak, and we are still on the side where we are increasing the number of cases. I’m really thinking this is going to be a year-long," said Katherine Wells, director of Lubbock Public Health, during a recent briefing, as reported by CNN. "I just think, it being so rural now, multistate, it’s just going to take a lot more boots on the ground, a lot more work to get things under control. It’s not an isolated population."

Public health officials are urging vaccination and heightened vigilance, particularly in affected states, to contain the spread of the outbreak.