MILWAUKEE (CBS 58) — A child in Texas has died from measles, marking the first death from the disease in the United States since 2015.

It comes as a measles outbreak is growing in west Texas, with 124 confirmed cases.

The Texas Department of State Health Services said the child who died was not vaccinated for the disease.

The spread aligns with a nationwide decline in childhood vaccinations, and Wisconsin has one of the lowest rates in the country.

The Wisconsin Department of Health Services estimates 84.8% of Wisconsin kindergarteners had both doses of the measles-mumps-rubella (MMR) vaccine in the 2023 to 2024 school year.

CDC data shows that is the second lowest rate in the country, behind Alaska at 84.3%.

Experts say that isn't nearly high enough to prevent an outbreak.

"Measles is probably one of the most contagious things on the planet, and so when these things do get going, they do take off like wildfire," said Dr. Jim Conway, medical director of UW Health's immunization program.

Dr. Conway calls the now-deadly measles outbreak in Texas "inevitable," as childhood vaccination rates have gradually decreased.

Conway says that's due to missed routine care during the COVID-19 pandemic and growing vaccine hesitancy.

"We did see this sort of global pandemic of vaccine hesitancy that has really taken root, and unfortunately really undermined many of these successes we've had with public health," Conway explained.

Measles starts as a fever, with red eyes, a red mouth, and a growing rash.

"It's got a very long incubation period," Conway said. "It can be many weeks, and people can be contagious before they even develop symptoms."

As it spreads, Dr. Conway says it can affect every part of the body, leading to infections, like pneumonia, and even blindness.

"Most people recover. Some of the people who recover have long-term sequelae, but some people are going to end up being hospitalized, and some people, unfortunately, are not going to make it through," he explained.

Dr. Conway says the measles-mumps-rubella vaccine has been recommended for children for more than 40 years as safe and effective protection.

The CDC notes a 95% vaccination threshold is needed to protect against outbreaks, and DHS data shows Wisconsin isn't even close.

"In the central and northern part of the state, we have counties that less than 50% of the kids are fully immunized," Conway said. "One case showing up there could spread widely, and we would be in the exact same boat as west Texas is currently."

Right now, there are no reported cases in Wisconsin.

An MMR vaccine can be given at any age, and Dr. Conway recommends talking to your health care provider if you or your children haven't received it.