Selection of Adjuvants for Enhanced Vaccine Potency

The advent of mass vaccination has saved millions of human lives and revolutionized the quality of life. Vaccination is currently one of the most cost effective ways of managing healthcare costs in both emerging and developed countries. Despite the long vaccine history and success, design and development of efficacious and safe vaccines has been traditionally semi-empirical. This is mainly due to our limited understanding of vaccination mechanism and its influencing factors. The most important factor is arguably the type and concentration of vaccine adjuvants. Until recently, however, only one type of adjuvant-aluminum salts, had been widely used within licensed human vaccines in the US, even though a variety of novel adjuvants have been evaluated in the past few decades. This review summarizes the key adjuvants that have been evaluated in recent years with an intention to facilitate more efficient development of vaccine products to combat human diseases.