Vaccination has been well recognised as a critically important tool in preventing infectious disease, yet incomplete immunisation coverage remains a major obstacle to achieving disease control and eradication. As medical products for global access, vaccines need to be safe, effective and inexpensive. In line with these goals, continuous improvements of vaccine delivery strategies are necessary to achieve the full potential of immunisation. Novel technologies related to vaccine delivery and route of administration, use of advanced adjuvants and controlled antigen release (single-dose immunisation) approaches are expected to contribute to improved coverage and patient compliance. This review discusses the application of micro- and nano-technologies in the alternative routes of vaccine administration (mucosal and cutaneous vaccination), oral vaccine delivery as well as vaccine encapsulation with the aim of controlled antigen release for single-dose vaccination.

Inadequate booster uptake threatens the success of immunization campaigns as seen with the recently rolled-out R21 malaria vaccine. The ability to administer both prime and boost immunizations with a single injection would therefore save lives and alleviate health care burdens. We present a platform for delayed delivery of the booster dose that is scalable with existing technology, easily injectable, and protective against malaria in vivo. Using chip-based microfluidics, we encapsulated the R21 malaria vaccine in polymer microcapsules that release their content weeks to months postinjection. Coinjecting microcapsules with the priming dose of the R21 vaccine elicited strong antibody responses in a mouse model and provided 85% of the protection of a standard prime/boost schedule. If confirmed in humans, these results would pave the way for rapid deployment of single-shot prime/boost vaccination, an urgently needed global health intervention.

Inadequate booster uptake threatens the success of immunisation campaigns as seen with the recently rolled-out malaria vaccine. Ability to administer prime-boost immunisation with a single injection would save lives and alleviate healthcare burdens. We present the first platform for delayed delivery of the booster dose, that is scalable with existing technology, easily injectable and highly protective against malaria. Using chip microfluidics, we encapsulated the R21 malaria vaccine into polymer microcapsules that release their content weeks to months post-injection. Co-injection with a priming dose elicited strong antibody responses in a mouse model and provided 85% of the protection of a standard prime-boost schedule. These results pave the way, for the first time, to the rapid deployment of single-shot prime-boost vaccination, an urgently needed global health intervention.