IgA Antibodies Reveal Covert Infection With Mpox Virus in People Living With HIV in the Community: A Prospective Longitudinal Cohort Survey

Covert mpox virus (MPXV) infection among people living with HIV (PLWH) remains poorly understood. This study aimed to investigate undetected MPXV infections through seroepidemiological analysis. We recruited 148 PLWH during July 2-9, 2023 (baseline), with 60 and 148 participants returning for 4- and 14-month follow-ups, respectively. PCR testing showed that all saliva and blood samples were negative for MPXV-DNA. The titers of IgG, IgA, and IgM were evaluated using ELISA with virions. MPXV-IgA and IgM were undetectable, 15 participants born before 1980 had low MPXV-IgG at baseline. At 14 months, 10 participants (6.8%) showed increased MPXV-IgG titers. All seroconverters had detectable neutralizing antibodies, and nine were MPXV-IgA positive. Further results showed that IgG seropositivity against MPXV proteins (A29L, A35R, B6R, E8L, H3L, and M1R) ranged from 0% to 80%, while IgA seropositivity ranged from 0% to 60% among the 10 participants at the 14-month. The B6R and E8L combination showed IgG detection comparable to whole virions, while E8L and H3L combination increased IgA seropositivity to 70%. The occurrence of MPXV covert infection among PLWH underscores the need to improve surveillance strategies in the community. The presence of MPXV-IgA in blood may offer a preliminary temporal signal of MPXV infection.