The person responsible for investigating the event will complete a ‘case investigation form’. This form asks a set of comprehensive questions that will provide all the information that is necessary to work out the relationship between the vaccine and the adverse events. Questions on the form include vaccination details and procedures, immunisation practices at the place where the vaccine was administered, cold chain and vaccine transport, community investigations (to identify clusters of cases), patient medical history, clinical examination and results of investigations.

The investigator will obtain the medical records of the person who experienced the adverse event. The investigator will not make a judgement themselves on the cause of the adverse event, but will submit these data to the provincial or the national immunisation safety expert committee (NISEC).