Development and clinical evaluation of a MPXV antigen-detecting rapid diagnostic test

To address the global emergence of mpox after the 2022 epidemic, a rapid and accurate diagnostic tool is needed at the point of care to identify individuals infected with mpox virus (MPXV) to prevent and control the spread of the virus. We designed an antigen-detecting rapid diagnostic test that exclusively detects MPXV without cross-reacting with the vaccinia virus by developing monoclonal antibodies against the MPXV nuclear capsid protein A5L (MPXV-A5L). The test results indicated that the detection limits were established at 0.5 ng/mL for MPXV-A5L and 4.4 × 10² ∼ 2.1 × 10³ pfu/mL for MPXV culture fluid. Clinical samples collected from MPXV patients showed a high sensitivity of 87 % at a qPCR cycle threshold of 25 or lower, with a specificity of 100 % for samples that tested negative in the qPCR. The test is an ideal rapid diagnostic tool for supporting clinical decision-making for people suspected of having MPXV infection in resource-poor settings.