J Infect Dis. 2015 Jul 15;212 Suppl 1:S12-6. doi: 10.1093/infdis/jiu568.
Stanley A. Plotkin.
Vaccines already developed have been enormously successful. However, the development of future vaccines requires solution of a number of immunologic problems, including pathogen variability, short effector memory, evoking functional responses, and identification of antigens that generate protective responses. In addition, different populations may respond differently to the same vaccine because of genetic, age, or environmental factors