Effectiveness of nanofiltration in removing small non‐enveloped viruses from three different plasma‐derived products

The objective of this study was to assess the ability of nanofiltration of albumin solution, prothrombin complex (PTC) and factor IX (FIX) to remove two small, non‐enveloped DNA viruses, parvovirus B19 (B19V) and torque teno virus (TTV). Virus removal was investigated with down‐scale experiments performed with sequential steps of 35‐nm and 15‐nm nanofiltrations of products spiked with virus DNA‐positive sera. Viral loads were determined by real‐time PCRs. The 15‐nm nanofiltration removed more than 4.0 B19V log from all the products, TTV was reduced of more than 3.0 log from albumin solution and FIX by 35‐nm and 15‐nm nanofiltrations, respectively, being viral DNA undetectable after these treatments. Traces of TTV were still found in PTC after the 15‐nm nanofiltration. In conclusion, nanofiltration can be efficacious in removing small naked viruses but, since viruses with similar features can differently respond to the treatment, a careful monitoring of large‐scale nanofiltration should be performed.