Severe form of mpox may be fatal in 15% of people with advanced HIV

Mpox on back of hands

Mustafa Kaya / iStock

Clinicians have identified a severe, flesh-eating form of mpox with a 15% death rate in HIV patients who have suppressed immune systems, according to a global case series published this week in The Lancet.

Starting on May 11, 2022, a network of clinicians from 19 countries evaluated 382 adult mpox patients who also had advanced HIV, including 27 of the 60 people globally who died by the end of the study on Jan 18, 2023.

The current global mpox outbreak, which began in May 2022, has infected a total of 86,209 people in 110 countries. Ninety-six of them have died. The authors noted that HIV patients have accounted for 38% to 50% of mpox cases.

Low CD4 counts tied to complications, death

Participants included 367 cisgender men, 4 cisgender women, and 10 transgender women. Median participant age was 35 years. At mpox diagnoses, 349 (91%) of 382 participants had HIV, 228 of 349 (65%) were adherent to antiretroviral therapy (ART), and 32 of 382 (8%) also had an additional infection related to their suppressed immune system.

Only 26 of the study participants (7%) had received the Jynneos mpox vaccine. Sixteen (4%) had been vaccinated before 2022, presumably for smallpox.

The median CD4 cell count (an indicator of immune function) was low, at 211 cells per millimeter cubed (cells/mm3), with 22% of patients having CD4 cell counts of less than 100 cells/mmand 25% with 100 to 200 cells/mm3. Just over half of patients had an undetectable HIV viral load.

Severe complications were more common in patients with a CD4 count less than 100 cells/mm3 than in those with more than 300 cells/mmand included necrotizing (flesh-eating) skin lesions (54% vs 7%), lung dysfunction sometimes accompanied by nodules (29% vs 0%), and secondary infections and sepsis (44% vs 9%).

A total of 107 patients (28%) were hospitalized, and 27 (25%) of them died. All deaths were among patients with CD4 counts of less than 200 cells/mm3, and most occurred in those with a high HIV viral load.

Severe complications were more common in patients with a CD4 count less than 100 cells/mm3 than in those with more than 300 cells/mm3.

The clinicians suspected an inflammatory immune reaction to mpox in 21 (25%) of 85 people started or restarted on ART, 12 (57%) of whom died. Sixty-two of 382 patients (16%) received the Tpoxx smallpox/mpox drug (tecovirimat), and 7 (2%) were given other antivirals (cidofovir or brincidofovir). Three cases of tecovirimat resistance were identified.

Prioritizing vaccinations for HIV patients

"We describe a severe form of mpox affecting mostly young men who have sex with men and which results in death in 15% of people with advanced HIV," lead author Oriol Mitja, MD, PhD, of the University Hospital Germans Trias in Barcelona, Spain, said in a Queen Mary news release.

"Health authorities should prioritise the vaccination of people living with HIV, particularly in countries with low levels of diagnosis or without universal free access to antiretroviral treatment."

In the study, the authors conclude, "A severe necrotising form of mpox in the context of advanced immunosuppression appears to behave like an AIDS-defining condition, with a high prevalence of fulminant dermatological and systemic manifestations and death."

In a related commentary, Isaac Nunez, MD, and Sergio Ivan Valdes-Ferrer, MBBS, PhD, both of the Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran in Mexico City, questioned the case-series authors' proposal to consider severe mpox an AIDS-defining condition.

"This stigma is so central to the global outbreak that monkeypox came to be called mpox, precisely to reduce discrimination regarding race and sexual orientation," they wrote.

"Considering mpox in general as an opportunistic infection (a term that applies to any-cause immunosuppression and not only HIV) rather than labelling fulminant mpox as an AIDS-defining condition could have the same positive connotations regarding bedside care (eg, increasing suspicion of other opportunistic infections) and preventing stigma."

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