Combined adjuvant-delivery system for new generation vaccine antigens: alliance has its own advantage

Vaccines are a significant historical accomplishment in medical science due to its significance in saving millions of lives around the world with a manifold decline in disease burden and health expenditure. Since last decade, extensive efforts in vaccine design based on rational and experimental set up prompts the acknowledgement of several protective antigens; however, the utilization of those antigens as intense safe vaccines is still far beyond their discovery. The advancement of accomplished vaccines will need the combination of numerous strategies. In this way, the vaccine can be capable of provoking an abundant and effective immunization to compete against antigens with minimal/no adverse effects on recipients. First, stable and striking enough on the pharmaceutical point of view. Second, application of rational and realistic approaches to select an appropriate combination of adjuvant, antigen and delivery vehicle in the suitable formulation. Different vaccine adjuvants-delivery system combinations were discussed here elaborately, which are approved/licensed for human vaccines and are in various phases of clinical trials and pre-clinical trials. Challenges/limitations associated with vaccine designing and parameters to be considered, approaches to be applied, using available adjuvants are also detailed.