Although the development of a vaccine to protect against SARS-CoV-2 infection has progressed at an unprecedented rate and produced an impressive volume of candidates for testing, many challenges lie ahead. The prior knowledge gained after SARS-CoV-1 was first discovered in 2003, and the subsequent emergence of MERS-CoV in 2012 provided a significant jumpstart, but the progress of SARS-CoV-2 vaccine development has already far outstripped the point of the blueprint created before COVID-19 became a pandemic. While a variety of platforms are simultaneously being innovated or adapted, they each have strengths and limitations, many of which relate to the delicate balance between safety and immunogenicity. Many shortcuts have been taken and will continue to be taken due to the urgency of the ongoing COVID-19 pandemic, but significant concerns need to be addressed. One such concern involves the accumulating data supporting the initial assessment that COVID-19 is disproportionately severe in older adults. In conjunction with the large body of work related to immune senescence, these findings indicate that vaccine design should take into consideration the impact of aging on vaccine efficacy (Nikolich-Žugich, 2018). Furthermore, questions remain regarding the possibility of antibody-dependent enhancement of COVID-19, with in vitro experiments, animal studies, and two studies of COVID-19 patients supporting this possibility (Cao, 2020, Tetro, 2020, Zhang et al., 2020a, Zhao et al., 2020a). Assuming vaccine candidates that can safely induce protective immune responses are identified, additional major hurdles will be the production and dissemination of a vaccine. For some types of vaccines, large-scale production will not be as much of an issue, and infrastructure already in place to produce current Good Manufacturing Practice (cGMP)-quality biologics can be repurposed, but this will only be applicable to a subset of the candidates (Thanh Le et al., 2020). In order to address the urgent need and stem the COVID-19 pandemic, regulatory agencies need to continue to support rapid testing and progression of vaccine candidates, companies need to disseminate important findings directly and openly, and researchers need to investigate correlates of protection using in-depth immune monitoring of patients with a broad range of clinical presentations and clinical trial participants. The newly announced Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) is designed to bring together numerous governmental and industry entities to help address this need.