Herpesvirus preparations, e.g. cultured HSV type 2, e.g. genetically disabled virus for vaccine use, can be purified, e.g. for subsequent pharmaceutical formulation, with solid phase affinity reagents containing sulfate- or sulfonate-comprising binding groups, e.g. sulfated polysacharide groups, e.g. heparin or dextran sulfate, and eluting e.g. with salt solutions. The process can be combined with other culture and harvesting steps.