Dear Editor-in-Chief,

Appropriate vaccine administration is essential for achieving optimal safety and efficacy in vaccination. It is crucial to administer the vaccine at the correct site and use the appropriate injection technique. Injecting too far to the side of the arm or too low on the arm risks injury to the axillary or radial nerve, which can cause burning or shooting pain during the procedure and may lead to nerve damage (neuropathy or paralysis). The COVID-19 vaccine should be injected into the deltoid muscle in the upper arm, specifically in its central and thickest portion. If there is insufficient muscle mass in the deltoid area or if, for any reason, the deltoid muscle is unsuitable, the alternative site for injection can be the vastus lateralis muscle in the anterolateral aspect of the thigh. Injection technique, along with the choice of needle length and gauge (diameter), as well as the injection site, are important considerations, as they can affect the immunogenicity of the vaccine and the risk of local reactions at the injection site.