WHO Admits to Releasing Pandemic Virus into Population via 'Mock-Up' Vaccines
...some manufacturers have conducted advance studies using a so-called “mock-up” vaccine. Mock-up vaccines contain an active ingredient for an influenza virus that has not circulated recently in human populations and thus mimics the novelty of a pandemic virus.
Time constraints mean that clinical data at the time when pandemic vaccines are first administered will inevitably be limited. Further testing of safety and effectiveness will need to take place after administration of the vaccine has begun.