Information on the HCAI interventions implemented in each
acute trust and their start dates had been collected previously
using detailed questionnaires with trust staff (Supplementary
Figure 1).5 These start dates were used in this study rather
than official campaign roll-out dates because actual implementation
of national campaigns varied within individual trusts
due to local practicalities or involvement in pilot studies.
Where discrepant dates were identified which could not be
resolved, the earliest start date of the campaign was used to
ensure that the earliest possible implementation was
captured. The five interventions covered in the study are
detailed in