‘Horrific’ form of mpox found to affect people with advanced HIV

A severe and "horrific" form of mpox has been identified in immunosuppressed people living with HIV, which appears to be deadly in about 15% of cases.

Solid organ transplant recipients, and those with blood cancers, may also be at risk, although no cases have yet been detected in such individuals.

Scientists are calling on people at high risk of HIV to get tested for the virus, along with anyone who tests positive for mpox, which was formerly known as monkeypox.

They would also like to see mpox added to the World Health Organization's list of severe infections that are particularly dangerous to people with advanced HIV, which could unlock greater financial and medical support for those at risk.

Since May 2022, about 85,000 cases of mpox and 93 deaths have been reported from 110 countries around the world. Many of these cases have been in men who have sex with men, and 38-50% of those diagnosed with mpox also live with HIV - the vast majority of whom are on HIV treatment and living healthy lives.

Prompted by reports of particularly severe mpox infections in patients with HIV, Prof Chloe Orkin, at Queen Mary University of London and Barts Health NHS trust, and colleagues examined 382 cases of people with advanced HIV disease and mpox, including 27 who had died of mpox during the current outbreak.

"The virus appears to be behaving completely differently in these individuals," said Orkin, whose findings are published in The Lancet. "Normally, the disease affects the area around the site of entry, but in this case it is disseminated all over the body and causing these massive destructive ulcerating skin lesions. It is also causing lung disease. It is horrific."

Based on current figures, this form of the disease appears to kill 15% of people with advanced HIV and immunosuppression - although it could be as high as 27% in those with the lowest CD4 cell counts (a marker of the extent to which HIV has weakened the immune system).

Not everyone with HIV is at risk of this type of mpox. Those who are taking antiretroviral treatment for HIV and who have a healthy CD4 count appear to experience similar symptoms, and the same prognosis, if they catch mpox as those who don't have HIV. "It is an unpleasant disease - I wouldn't wish it on anyone - but it is self-limiting," Orkin said.

However, people whose CD4 count has fallen below 200 cells/mm3 are at risk. This could include people living with undiagnosed HIV, because symptoms of the disease often don't show up until CD4 counts have dropped below a critical level.

"Everyone with mpox should be tested for HIV, and if someone has HIV and gets mpox, their CD4 status must be measured," said Orkin. She also urged those who have put off learning their HIV status to get tested. "Things have changed. We have a disease which is now circulating at low levels in humans, which is potentially lethal for people with HIV, and they die within a month," she said. "If you know someone who is vacillating about getting a test, encourage them."

The Terrence Higgins Trust, a HIV charity, said it supported the researchers' recommendation that people diagnosed with mpox are also offered an HIV test. "The vast majority of people living with HIV in the UK are successfully managing their HIV with medication and therefore not immunosuppressed. But this is vital research into the impact of mpox on those living with undiagnosed, unsuppressed or untreated HIV that must be acted on," said Alex Sparrowhawk, the charity's HIV and ageing manager.

While greater awareness of mpox had led to many gay and bisexual men coming forward to be vaccinated, and a significant drop in cases, it was important not become complacent, he added. "This is also a reminder that it's not too late to get vaccinated with both first and second doses available from sexual health clinics, and two doses offering maximum protection against the virus."

"Although mpox is rarely severe for those of us whose HIV is controlled with treatment, the rates of serious illness and mortality as a result of mpox for people with untreated or unsuppressed HIV are worrying," said Matthew Hodson, executive director of the HIV charity NAM aidsmap.

"Our success in curbing new mpox infections may have led us to think mpox is no longer a cause for concern. This data highlights that mpox remains a significant threat to the lives of people with advanced HIV, a group who may not be getting the healthcare they need, including mpox vaccination."