Background: Good communication between healthcare professionals and their patients is essential to enlighten the benefits and risks of vaccination. Despite the availability of effective vaccines, reluctance prevails, sometimes fuelled by sub-optimal communication leading to a lack of trust. An evaluation of the effectiveness of a communication strategy for which healthcare professionals are trained has yet to be carried out.

Objective: Systematic review of studies with a randomized controlled trial (RCT) to define and evaluate the impact of healthcare professionals' communication on patients' vaccine adherence.

Methods: We performed a structured search on Medline, Embase, CENTRAL, PsycINFO and CINAHL. The studies selected include those involving healthcare professionals authorized to administer vaccines according to Canadian guidelines. Primary outcomes include vaccination rate or vaccine hesitancy rate.

Results: Nine articles were included. Five studies (n=5) reported intervention effectiveness according to vaccine adherence. The results are largely represented by parental vaccine hesitancy for human papillomavirus (HPV) or childhood vaccination, while three studies (n=3) target the general population. The risk of bias relative to the studies is either low (n=7) or of some concern (n=2).

Conclusion: The effectiveness of communication varies according to the studies and knowledge acquired through training. Future studies will need to examine communication with healthcare professionals in order to establish a consensus on optimal and appropriate training.