Are the anatomical sites for vaccine administration selected judiciously?

Route of vaccine administration plays an important role in the development of immune response. Antigen administered via different anatomical sites interacts with diverse subsets of antigen presenting cells. Diverse population of antigen presenting cells directs a drastically different immune response. Initially, the recommended routes for vaccine administration were also selected on the basis of clinical trials conducted for the drug molecules. However, physicochemical and pharmaceutical behaviors of proteins (antigens) and chemical compounds are entirely different. Most of the commercial vaccines are injected in the arm or in the scapular region (deltoid muscle). Vaccine administered to these conventional anatomical sites has failed to induce desired immune response due to lack of optimum level of antigen presenting cells. In this review, we have discussed the importance of the selection of anatomical sites for vaccine administration. Mere selection of an optimum site for vaccine administration may drastically change the immune response of the current marketed formulations without any alteration in their existing production plans.