Vaccines for emerging pathogens: from research to the clinic

Williamson, E. D.

New technologies for vaccine formulation and administration would be advantageous in the context of rapid vaccination on a large scale to curtail disease outbreaks. In their article, Wallis, Shenton and Carlisle [4] review novel approaches for the design, delivery and administration of vaccines. The authors consider a range of vaccine formulations and presentations (e.g. virus-like particles, conjugate vaccines, liposomes, live attenuated vectors) and parenteral (conventional and novel such as transdermal aided by ultrasound) administration routes. They discuss the potential for self-administration of vaccines (e.g. by oral and intranasal routes). Additionally, the need to target the immune system appropriately to induce both serological and cellular responses in systemic and mucosal compartments has been considered. In this context, the review by Miquel-Clopes et al. [5] focuses on vaccines which are designed to induce mucosal immunity to protect mucosal surfaces (principally the respiratory, inhalational, gastrointestinal and genitourinary tracts) from pathogen invasion. The authors review the handful of mucosal vaccines for either human or veterinary use which are already licensed. They make the case that the use of effective vaccine delivery systems and the avoidance of immune tolerance induction are essential factors in the development of vaccines inducing mucosal immunity. This is a theme to be expanded in the second part of this review series, where there will be a review of current developments in oral vaccine delivery technologies, and the selection of appropriate preclinical models to determine vaccine safety, immunogenicity and efficacy and from which to derive immune correlates of protection. The latter are required to understand the mechanism of action of candidate vaccines and to identify potential surrogate markers of vaccine efficacy, to apply to clinical trials. Additionally, potential pathways will be discussed for regulatory approval of vaccines for emerging pathogens.