CHICAGO: People with severely weakened immune systems, such as those infected with HIV, can experience severe symptoms and even die from a monkeypox infection, according to a U.S. study released.

The study looked at cases of 57 U.S. patients hospitalized with severe monkeypox complications. Almost all (83%) had severely weakened immune systems, most often because of infection with the human immunodeficiency virus (HIV). Many of those patients were not being treated for the virus that causes AIDS.

"Monkeypox and HIV have collided with tragic effects” Dr. Jonathan Mermin, leader of the monkeypox response for the U.S. Centers for Disease Control and Prevention (CDC), said in a statement.

“Today’s report reminds all of us that access to monkeypox and HIV prevention and treatment matters - for people’s lives and for public health,” he said.

More than 90 countries where monkeypox is not endemic have reported outbreaks of the viral disease, which the World Health Organization has declared a global health emergency. Confirmed cases have reached 76,757.

Just over 28,000 people in the United States have been infected with monkeypox since the start of the outbreak in May. Cases in the United States started peaking in mid-August and have since dropped sharply, helped by the rollout of vaccines.

Deaths outside of Africa, where the virus is endemic, are rare, as are deaths caused by the form of the virus now circulating in the United States - Clade IIb.

For the study, health officials investigated some of the most severe cases of monkeypox, which spreads through close contact with an infected person.

Overall, it found that 47 of these individuals were also infected with HIV, yet only four of them were receiving antiretroviral therapy, powerful drugs that keep the virus in check. Most (95%) were male, and 68% were Black.

According to the analysis, 17 patients required care in an intensive care unit, and 12 have died, including five in which monkeypox was a contributing factor or the confirmed cause of death.

The researchers urged healthcare workers to test all sexually active patients with suspected monkeypox infections for HIV at the time of monkeypox testing, unless the patient's HIV status is already known.

For those with suspected monkeypox infections who test positive for HIV, the CDC urged providers to start the patient on monkeypox treatment as soon as possible, potentially even before monkeypox infection is confirmed. The agency also recommended that doctors start HIV treatment for those who test positive for that virus as soon as possible.