The heat sensitivity of B19 in liquid was clearly different from that of CPV. Significantly, the efficiency to inactivate B19 and reduce its infectivity following heating in liquid was mainly affected by the composition of the solutions used for virus suspension.

If by rare chance SARS-CoV contaminates source plasma, there should be no or only minor risk of this virus infection, due to sufficient inactivation by the 60 degrees C 10 h liquid heating step, although we must pay attention to the composition used for blood product preparation.

Background and ObjectiveTo investigate the physico-chemical properties of hepatitis E virus (HEV) with regard to inactivation/removal, we have studied four isolates with respect to sensitivity to heat during liquid/dry-heating as well as removal by nanofiltration. Materials and MethodsHepatitis E virus in an albumin solution or phosphatebuffered saline (PBS) was liquid-heated at 60 ° C for a preset time. HEV in a freezedried fibrinogen containing stabilizers was also dry-heated at 60 or 80 ° C for a preset time. In addition, to clarify the removal of HEV, the purified virus in PBS was filtered using several types of virus-removal filter (nanofilters) that have different pore sizes. HEV infectivity or genome equivalents before and after the treatments were assayed by a semiquantitative cell-based infectivity assay or quantitative polymerase chain reaction assay, respectively.Results Hepatitis E virus isolates in albumin solutions were inactivated slowly at 60 ° C for 5 h and the resultant log reduction factor (LRF) was from 1·0 to ≥ 2·2, whereas the virus in PBS was inactivated quickly to below the detection limit and the LRF was ≥ 2·4 to ≥ 3·7. The virus in a freeze dried fibrinogen containing trisodium citrate dihydrate and L -arginine hydrochloride as stabilizers was inactivated slowly and the LRF was 2·0 and 3·0, respectively, of the 72 h at 60 ° C, but inactivated to below the detection limit within 24 h at 80 ° C with an LRF of ≥ 4·0. The virus in PBS was also confirmed as to be approximately 35 nm in diameter by nanofiltration. These results are useful for evaluating viral safety against HEV contamination in blood products. ConclusionThe sensitivity of HEV to heat was shown to vary greatly depending on the heating conditions. On the other hand, the HEV particles were completely removed using 20-nm nanofilters. However, each inactivation/removal step should be carefully evaluated with respect to the HEV inactivation/removal capacity, which may be influenced by processing conditions such as the stabilizers used for blood products.

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