In efficacy testing, the chemical inactivation cannot be determined for all viruses, because some of the viruses relevant to human medicine cannot be cultivated sufficiently or may pose too high a risk to laboratory staff when carrying out the tests. Hence, surrogate viruses are used as alternative.
They are selected on the basis of their morphological similarities to the viruses relevant to human medicine. One example is the BVD virus, which has been approved by the Robert Koch-Institute (RKI), the German Registered Association for Combating Viral Diseases (DVV), and by the German Society for Hygiene and Microbiology (DGHM) as surrogate to HCV.
However, according to the RKI, the suitability of FCV and MNV as surrogate viruses to Noroviruses can so far not be conclusively assessed on the basis of existent data.