Recently, a study concerning a veterinary live virus vaccine, which was produced under protein-free conditions (devoid of any animal or human derived substances), showed that such a vaccine was as efficacious and safe as a classically produced vaccine (under serum-conditions) (Makoschey et al., 2002) . This indicates very clearly that the use of serum for the production of viral vaccines, in particular, and of biologicals, in general, is an anachronism and that the efficient replacement of non-animal derived serum-supplements is feasible.