Samples
Five serum samples from PCR-confirmed MPXV-infected individuals and six serum samples from confirmed (by PCR or serology) CPXV-infected individuals were collected in the course of the routine diagnostics in the Consultant Laboratory for Poxviruses at the Robert Koch Institute. Five serum samples from vaccinated volunteers (IMVANEX) were collected four weeks after the first vaccine dose (n=1) or two (n=3) or three (n=1) weeks after the second vaccine dose. For establishment of the ELISA a panel of 28 sera (25 sera from routine MPXV diagnostics and three pre-immune sera from volunteers prior to IMVANEX vaccination) was employed. All sera were titrated by IFA to determine end-point titres for both IgM and IgG antibodies as described below. Sera were selected to cover a broad range of reactivities, including sera with low (below 1:80), medium (1:320) and high (1:1280 and above) titres. Ethical clearance was obtained from the Berliner Ärztekammer (BÄK Eth-44/22).