Texas has confirmed what appears to be the first death of a person diagnosed with monkeypox in the United States. 

The Texas Department of State Health Services (DSHS) said in a release on Tuesday that the patient was an adult living in Harris County who was severely immunocompromised. Officials are investigating what role the virus played in the person’s death. 

Texas Health Commissioner John Hellerstedt said in the release that monkeypox is a particularly serious disease for those with weakened immune systems. The department said the virus is painful for most people but not life-threatening. 

“We continue to urge people to seek treatment if they have been exposed to monkeypox or have symptoms consistent with the disease,” Hellerstedt said. 

The Centers for Disease Control and Prevention (CDC) had confirmed more than 18,000 cases of the virus in all 50 states as of Monday, but so far officials had not confirmed any deaths. The CDC has only confirmed 15 deaths worldwide from the virus throughout this year’s monkeypox outbreak. 

The release advises people to contact their health care provider if they experience fever, chills, swollen lymph nodes and a new, unexplained rash. 

The virus has mostly spread among men who have sex with men, but anyone can get it through close, direct contact with an infected person. People who are diagnosed with monkeypox should stay home and avoid close contact with others until the rash has fully gone away and a new layer of skin has completely formed, according to the release. 

The Biden administration announced on Monday that it would invest about $11 million for the domestic production of the Jynneos smallpox vaccine, which is also effective at preventing monkeypox. About 200,000 first doses of the Jynneos vaccine have been administered so far. 

Vaccines are encouraged for those who have been in close contact with infected patients and those who have had multiple sexual partners in the past two weeks in areas with confirmed cases. 

Health officials said last week that monkeypox cases in the U.S. appeared to be trending downward.