Intramuscular vaccine administrations including the adoption of “Zeta-track technique” & “without aspiration slow injection technique” (ZTT & WASiT): a prospective review

Abstract Objective To review the current literature on the practice of intramuscular injections (IMIs), focusing on immunizations. Methods The present study comprises 2 reviews, characterized by high-quality evidence, pertaining to the deployment of the slow injection technique without aspiration (referred to in this paper as the without-aspiration slow injection technique [WASiT]) and combined with the Zeta-track technique (ZTT). The literature review is oriented toward the analysis of 2 features associated with IMIs techniques: safety and pain, integrating new evidence on vaccinee positioning for each muscle site and general relaxation techniques in the multi-parametric analysis. Results The rigorous and in-depth reviews in the current study reveal the usefulness of including, among the international guidelines for via intramuscular immunizations, the adoption of WASiT only for compliant vaccinees, and in combination with all validated techniques for IMIs, and the use of ZTT limitedly if specific well-developed muscles are indicated. All the technique’s limitations are exposed. Conclusions Future research directions are presented by including the author’s study designs to provide indirect evidence for the validity of the rationale of the slow injection technique using scientific methods, and for the conduction of future randomized controlled trials (RCTs) focused on revisiting the adoption of ZTT in a dynamic and integrated immunizations protocol in anterolateral thigh (ALT), ventrogluteal (VG), and also in the deltoid muscle, in the specific cases analyzed.