Nucleic acid extraction and mpox q-PCR
After a heat inactivation step (12 minutes at 70°C), nucleic acids (500µL of samples) were extracted using MagNA Pure LC 2.0 Instrument (Roche, Meylan, France) and eluted in 100µL.  Mpox virus specific real-time PCR assay (qPCR) validated by both Centers for Disease Control & Prevention (CDC)9 and  French Orthopoxvirus national reference center10 was performed11. An exogenous internal extraction and amplification control (IEAC) was added to each sample before extraction (Simplexa™ Extraction and Amplification Control Set, DiaSorin, Saluggia, Italy)12. Negative controls were added to each extraction batch and a positive control (DNA extracted from a MXPV cell culture given by the French Orthopoxvirus national reference center) was tested in each PCR run.