Emerging infectious disease laboratory and diagnostic preparedness to accelerate vaccine development

Roberts, Christine C.

Reagents for newly emergent infectious diseases like MERS-CoV and ZIKV were not readily available from commercial vendors at the outset of vaccine development programs. As such, individual vaccine projects, including our own, had to rely on internally developed clinical assays to understand vaccine-related immune responses and to detect prior or current infections. 4, 5 Lack of standardization, however, can confound the interpretation of results from studies using different "home brew" assays across multiple laboratories such that study results cannot be directly compared in the absence of an accepted international standard or a proficiency panel of samples. 2, 10 The vast experience of our DNA vaccine consortium allowed us to develop MERS-CoV-and ZIKV-specific tests such as ELISA, virus neutralization and ELISpot early in the development and pre-clinical testing of the respective plasmid DNA vaccine constructs. [4] [5] [6] 8 These assays were evaluated for consistent performance throughout pre-clinical studies and we were able to adapt their use to support our Phase 1 and Phase 1b/2a studies of GLS-5300 MERS-CoV vaccine and two Phase 1 GLS-5700 ZIKV vaccine clinical trials. 7 As these vaccines move further into clinical development, work will need to continue to transition from our pre-clinical and early stage standards to well sourced and characterized human control reagents. The concern always remains, however, that the inability to use formally characterized and internationally accepted reagents and controls in early versions of vaccine clinical assays can result in maintenance challenges or regulatory hurdles later in the vaccine assays' life cycle. 37