A method for producing and purifying a wild type, an attenuated and/or a recombinant Orthopoxvirus, comprising the following steps: a) preparing a culture of packaging cells b) infecting the packaging cell culture with an Orthopoxvirus c) culturing the infected packaging cells until progeny Orthopoxvirus is produced d) incubation in presence of one or more nucleases e) recovering the Orthopoxviruses from the culture supernatant and/or the packaging cells f) adding monovalent salts to the Orthopoxviruses recovered in step e)under suitable conditions to inhibit the nuclease(s) activity and to avoid the adsorption of said Orthopoxviruses to the anion exchange adsorbent in step g) g) contacting the mixture obtained in step f) with an anion exchange adsorbent under suitable conditions to allow the capture of nucleic acids h) clarifying the mixture obtained in step g) under suitable conditions to allow the withdrawal of the cellular debris i) washing of the anion exchange adsorbent with a solution comprising monovalent salts under suitable conditions to recover the remained Orthopoxviruses in the flow through j) concentrating the flow through obtained in step h) and the flow through obtained in step i) k) diafiltrating the fraction comprising the Orthopoxviruses obtained in step j).
