Background: This systematic review was conducted as part of a 10-year update to a clinical practice guideline about reducing distress during vaccine injections and evaluated procedural interventions (injection techniques) that clinicians and organizations can use. Altogether, 4 clinical questions were included: (1) no aspiration prior to injection, (2) fast injection, (3) injecting the vaccine causing the most distress last, and (4) reducing fear cues prior to injection. Methods: Panel members voted on clinical questions and outcomes, as per GRADE methodology. A search strategy was executed across five databases: MEDLINE, EMBASE, APA PsycINFO, CINAHL, and ProQuest Dissertations. Randomized and quasi-randomized controlled trials involving individuals undergoing vaccination across the lifespan were eligible and identified in a stepwise fashion involving at least two reviewers. The critical outcome was distress, assessed by vaccine recipients or observers. Data were combined using standardized mean difference (SMD) with 95% confidence intervals. Summary statements were developed according to certainty of evidence and magnitude of effect (threshold SMD ≥0.2). Results: Altogether, 12 studies were included. Meta-analysis of 6 trials indicates that injecting without aspiration may result in a reduction in distress (SMD=−0.77, low certainty), as reported by vaccine recipients and observers. Fast injection may reduce distress slightly, according to self- and observer-report in two trials (SMD=−0.27, low certainty). Injecting the vaccine that causes the most distress last likely reduces distress (SMD=−0.73, moderate certainty), as reported by observers in 4 included trials. One trial providing indirect evidence demonstrates that reducing fear cues may reduce distress (SMD=−0.26, very low certainty), but the evidence is very uncertain. Conclusions: Procedural interventions are associated with benefit on vaccination distress and provide feasible options for clinicians and organizations to improve the vaccination experiences of vaccine recipients.
Taddio et al. (Thu,) studied this question.