A possible second measles death has been recorded in the U.S. this year after a New Mexico resident tested positive for the virus following their death.

The New Mexico Department of Health (NMDOH) said on Thursday the individual was unvaccinated and that the official cause of death is still under investigation.

The first measles death this year was reported in an unvaccinated school-aged child linked to an outbreak in western Texas.

The Texas death was the first measles death recorded in the U.S. in a decade, according to data from the Centers for Disease Control and Prevention (CDC).

New Mexico has reported a total of 10 measles cases so far this year, according to NMDOH. Many of the cases have been confirmed in Lea County, which borders western Texas.

Health officials suspect there may be a connection between the Texas and New Mexico cases, but a link has not yet been confirmed.

Health officials have been urging anyone who isn’t vaccinated to receive the measles, mumps, rubella (MMR) vaccine.

The CDC currently recommends that people receive two vaccine doses, the first at ages 12 to 15 months and the second between 4 and 6 years old. One dose is 93% effective, and two doses are 97% effective. Most vaccinated adults don’t need a booster.

“We don’t want to see New Mexicans getting sick or dying from measles,” Dr. Chad Smelser, deputy state epidemiologist for NMDOH, said in a statement. “The measles-mumps-rubella vaccine is the best protection against this serious disease.”

In western Texas, an outbreak has grown to 159 cases, according to new data released Tuesday.

Almost all of the cases are in unvaccinated individuals or individuals whose vaccination status is unknown, with 80 unvaccinated and 74 of unknown status. At least 22 people have been hospitalized so far, according to the Texas Department of State Health Services (DSHS).

Children and teenagers between ages 5 and 17 make up the majority of cases with 74, followed by 53 cases among children ages 4 and under.

The CDC has separately confirmed 164 cases in nine states so far this year in Alaska, California, Georgia, Kentucky, New Jersey, New Mexico, New York, Rhode Island and Texas.

The total, however, is an undercount due to delays in reporting from states to the federal government.