Boehringer Ingelheim VPH is home to one of the few laboratories equipped to handle FMD viruses. It demonstrates technical proficiency in Virus Neutralizing Tests (VNTs), as well as epidemiological and technical field trial expertise to address inquiries related to PVM. A medium-scale controlled field trial employing a protection-correlated method such as VNT is more valuable than a large-scale field trial using a poorly protection-correlated method like ELISA, even when extrapolating findings to a larger population (Figure 2). In other words, conducting a PVM with a smaller number of animals via a VNT-based study carries more weight than a study involving a larger number of animals using a poorly correlated method such as ELISA. However, both methods have their respective advantages and disadvantages, which should be carefully considered when planning a PVM (Figure 2).
Which type of trial for PVM?
100-500
30-60
5
Small scale
Medium scale
Large scale
EXPERIMENTAL TRIAL • Experimental unit • Homogeneous group of animals (animal segment, age, breed...) • Full control
CONTROLLED FIELD TRIAL • One or few farm(s) • Homogeneous group of animals (animal segment, age, breed...) and recorded • Vaccination controlled
FIELD TRIAL • Several farms
• Heterogeneous groups of animals (animal segment, age, breed...) preferably recorded
• Vaccination recorded (not fully controlled…)
Real life. Potential of a vaccine in the field, in normal conditions. Risks of interfering events
Not real life. Assess best potential of a vaccine
Close to real life. Potential of a vaccine in the field, in good condition
Efficacy of vaccine
Effectiveness of vaccination campaign
Figure 2: PVMs can consist of experimental, controlled field trial or field trial and is largely dependent on the size of the tested population. It can be directly correlated to vaccine efficacy in small scale trials and effectiveness of a vaccination campaign in larger-scale trials.
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