Zika virus (ZIKV) is a re-emerging flavivirus that is primarily transmitted via the blood meals of a mosquito although sexual and vertical transmission from mother to unborn fetus have been well-documented. It has caused sporadic outbreaks since it was first identified to cause human infections in 1950s. During the 2015-2016 outbreak of ZIKV, millions of people in the Americas were suspected or confirmed to be infected, causing WHO to declare the outbreak a public health emergency.
Although the global incidence of ZIKV disease has declined since 2017, ZIKV infections are spreading silently with limited global surveillance in at least 89 countries and territories. There is a pressing need to develop an effective vaccine suitable for equitable distribution globally. Consequently, we previously developed a proprietary DNA vaccine encoding secreted non-structural protein 1 of ZIKV (pVAX-tpaNS1) to elicit rapid protection in a T-cell dependent manner in mice. In the current study, we evaluated the stability, efficacy and immunogenicity of delivering this DNA vaccine into the skin using a clinically effective and proprietary high-density microarray patch (HD-MAP). Dry-coating of pVAX-tpaNS1 on the HD-MAP device resulted in no loss of vaccine stability at 40 °C storage over the course of 28 days. Vaccination of mice (BALB/c) with the HD-MAP-coated pVAX-tpaNS1 elicited a robust anti-NS1 IgG response in both the cervicovaginal mucosa and systemically and afforded protection against live ZIKV challenge. Furthermore, the vaccination elicited a significantly higher magnitude and broader NS1-specific T helper and cytotoxic T cell response in vivo compared to traditional needle and syringe intradermal vaccination. Overall, the study highlights distinctive immunological advantages coupled with an excellent thermostability profile of using the HD-MAP device to deliver a novel ZIKV DNA vaccine.