Monkeypox can be fatal for people with HIV or weak immune systems

People with severely weakened immune systems, such as those infected with the AIDS virus, can experience severe symptoms and even die from a monkeypox infection, according to a US study released on Wednesday.

The study analyzed cases of 57 American patients hospitalized with severe complications from monkeypox. Almost all (83%) had a severely weakened immune system, most often due to infection with the human immunodeficiency virus (HIV), which causes AIDS. Many of these patients were not being treated for the virus.

“Smallpox and HIV collided, with tragic effects,” said Dr. Jonathan Mermin, leader of the monkeypox response at the US Centers for Disease Control and Prevention (CDC), in a statement. “Today’s report reminds all of us that access to smallpox and HIV prevention and treatment is important — 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 reached 76,757.

Just over 28,000 people in the United States have been infected with monkeypox since the outbreak began in May. Cases in the US began to peak in mid-August and have since dropped sharply, with the help of vaccines.

Deaths outside 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 serious cases of monkeypox, which is spread by close contact with an infected person. Overall, 47 of these individuals were also found to be infected with HIV, but only four of them were receiving antiretroviral therapy, powerful drugs that keep the virus in check. The majority (95%) were male and 68% were black.

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

The researchers asked healthcare providers to test all sexually active patients with suspected monkeypox infections for HIV at the time of testing for smallpox, unless the patient’s HIV status was already known.

For those suspected of having smallpox infection from the monkeys who tested positive for HIV, the CDC urged providers to begin treating the patient as soon as possible, potentially even before the monkeypox infection was confirmed. The agency also recommended that doctors start HIV treatment as soon as possible for those who have tested positive for the virus.