Current Status of Zika Virus Vaccines: Successes and Challenges

Abstract

The recently emerged Zika virus (ZIKV) spread to the Americas, causing a spectrum of congenital diseases including microcephaly in newborn and Guillain-Barré syndrome (GBS) in adults. The unprecedented nature of the epidemic and serious diseases associated with the viral infections prompted the global research community to understand the immunopathogenic mechanisms of the virus and rapidly develop safe and efficacious vaccines. This has led to a number of ZIKV vaccine candidates that have shown significant promise in human clinical trials. These candidates include nucleic acid vaccines, inactivated vaccines, viral-vectored vaccines, and attenuated vaccines. Additionally, a number of vaccine candidates have been shown to protect animals in preclinical studies. However, as the epidemic has waned in the last three years, further development of the most promising vaccine candidates faces challenges in clinical efficacy trials, which is needed before a vaccine is brought to licensure. It is important that a coalition of government funding agencies and private sector companies is established to move forward with a safe and effective vaccine ready for deployment when the next ZIKV epidemic occurs.

Keywords: ADE; Zika virus; correlates of protection; immunoinformatics; vaccine platforms and vaccine candidates.

Figure 1

Schematic of various ZIKV vaccine platforms. Three major platforms: inactivated, subunit, and live attenuated/viral-vectored vaccines have been used to generate a number of vaccine candidates for preclinical and clinical testing. A variety of approaches and immunogens as shown were used. Immunoinformatics-based peptide vaccines have not been generated/tested (???). MV, measles virus; Ad, adenovirus; VSV, vesicular stomatitis virus; VV, vaccinia virus.