WHO activities towards the three Rs in the development and control of biological products.

WHO supports the concept of replacement, reduction and refinement of the use of in vivo methods for biologicals production and control, and regularly conducts reviews of its recommended procedures to allow reduction in the use of animals. The coordination of collaborative studies, publication of standardized methods, and holding of workshops on the use of these methods contributes to their use. The neurovirulence test for oral poliovaccine is probably the single most visible animal test for which alternative methods are sought. Collaborative studies on alternative methods for screening products are currently being sponsored by WHO. The use of Vero cells rather than primary monkey kidney cells for poliovaccine production can avoid the use of many monkeys. Cell banks of Vero and HEp-2 cells have been developed by WHO, tested for virus sensitivity and freedom from adventitious agents, and are available for vaccine production and control, replacing primary animal cells. For the future, final product testing will increasingly be directed towards establishment of consistency of production rather than potency. By supporting the validation and use of this approach, WHO can effectively influence more rational animal use in biological production and control.