The low to very low quality of the evidence of studies included in this review provides insufficient evidence to determine with certainty which interventions are most effective in changing professional behaviour and in what contexts. However, interventions that may be worth further study are educational interventions involving more than one active element and that are repeatedly administered over time, and interventions employing specialised personnel, who are focused on an aspect of care that is supported by evidence e.g. dentists/dental auxiliaries performing oral care for VAP prevention.