Amidst the growing global outbreak of mpox, which has affected over 90,000 people in 110 countries, a study published in The Lancet Microbe, co-led by IrsiCaixa and the Fight Infections Foundation, has compared the immune response to mpox in people with and without HIV. The study, conducted in Barcelona with the participation of 33 individuals, focused on analyzing how the immune response influences the severity of the disease and the speed at which the body eliminates the virus.

The results have shown that both people with HIV (14 participants) and those without HIV (19 participants) experienced a disease of similar severity and took approximately the same time to clear the virus from their bodies. It is important to note that, in this study, the group of participants with HIV had a good average count of CD4⁺ T cells, and 78% had undetectable HIV levels under antiretroviral treatment.

During the study, the scientific team identified that early and robust antibody responses, both IgG and IgA, are associated with milder disease and faster virus clearance. They also determined that a higher number of T cells specific to mpox is linked to greater virus elimination.

Although antibody levels decreased more rapidly in participants with HIV, T cell responses against mpox remained strong up to 6 months after diagnosis, regardless of HIV status. This suggests that antibodies are crucial for early infection control, while sustained T cell responses are essential for long-term management of the virus, potentially contributing to milder cases of reinfection.

The study emphasizes the need for further research, especially in people with advanced HIV, to better understand long-term protection and develop more effective public health strategies for future outbreaks of mpox.