Level of Inactivation

In order to minimise the risk of transfusion transmission, pathogen inactivation (PI) technologies need to inactivate high titres of a large number of pathogens (mean log reductions of 4 or more).

A pathogen inactivation system that provides only a 2 log reduction in bacteria would have roughly a 1 in 100 probability of incomplete inactivation, even without proliferation of the bacteria prior to PI treatment. As the inactivation process is often done 24 to 36 hours after the collection, this allows bacteria to increase to much higher concentrations, and requires higher log reductions. If just a few bacteria escape inactivation, they may further proliferate during storage to levels that are capable of causing sepsis.

The INTERCEPT™ Blood System shows robust inactivation for bacteria, offering a mean log reduction between 4.5 and >10.6. Studies have also demonstrated the robustness of the INTERCEPT inactivation process by performing the pathogen inactivation step 24 to 36 hours after the inoculation of slow and fast growing bacteria in different types of platelet concentrates, representing routine conditions.

The efficacy of the INTERCEPT Blood System was demonstrated in 2006 when a chikungunya epidemic occurred on the French island of Réunion, in the Indian Ocean. When approximately one third of the island’s 900,000 inhabitants were infected by the virus, local blood collection was suspended. After implementation of the INTERCEPT Blood System on the island in 2006, no cases of chikungunya transmission via blood components have been reported.¹

Similar experiences occurred in Guadeloupe, Martinique, French Polynesia and Puerto Rico, where more recent outbreaks of chikungunya and dengue caused severe problems.

A study by Aubry et.al ⁽²⁾ was recently published in the Transfusion journal in which it was shown that the INTERCEPT treatment is able to inactivate Zika virus in plasma. The viral load in the pre-inactivation samples were 6.46 to 6.63 log TCID₅₀ / ml, no viral replication was found in the plasma samples directly after inactivation.

Studies have also demonstrated the more robust pathogen inactivation efficacy of the INTERCEPT Blood System versus other pathogen inactivation systems for viruses and bacteria.

Robust pathogen inactivation of platelets suspended in PAS and plasma.

Inactivation efficacy of INTERCEPT™ was more robust for all bacteria tested at high or low titres.
S.Y. Kwon et al., Vox Sang. (2014) 107(3), 254-260

Source:
1. Rasonglès P, et al., Transfusion of platelet components prepared with photochemical pathogen inactivation treatment during a Chikungunya virus epidemic in Ile de La Réunion, Transfusion (2009) 49, 1083-1091
2. Aubry M, et all., Inactivation of Zika virus in plasma with amotosalen and ultraviolet A illumination, Transfusion 2016, Jan;56(1):33-40.DOI:10.1111/trf.13271. Epub 2015 Aug 18.