DNA-based Zika Vaccine Safe and Effective

An Epidemic without Vaccination
Although more than 60 years have passed since the discovery and first reported human cases of the zika virus, no vaccine has been developed to provide immunity from the virus successfully. Currently, there are no licensed vaccines against Zika virus infection. In 2015 and 2016, Zika virus spread rapidly through Brazil, the Caribbean, and even into the southern United States.

Zika virus spreads through the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus), mother-to-child, through sex, through blood transfusion, and through hospital and healthcare setting exposure.

Clinical Trial for Zika Vaccine GLS-5700
A research team at the Perelman School of Medicine at the University of Pennsylvania along with research teams from Miami and Quebec City enrolled 40 participants in the safety trial between August and September of 2016. Two groups of 20 participants received either one or two milligram doses of the vaccine candidate intradermally at zero, four, and twelve weeks. Each dosage was followed by the delivery of small electric currents into the skin at the site of injection, known as electroporation (EP), to facilitate optimal vaccine uptake, production of the intended antigen, and immune responses.

The Test Outcome
Two weeks after participants received the third and final dose of the vaccine, 100 percent developed Zika-specific antibodies and 80 percent developed significant neutralizing antibodies against the virus. Importantly, serum from the study participants was able to protect immune-compromised mice from developing the disease after infection with Zika virus, indicating that the vaccine-induced antibodies can prevent infection and disease in vivo. No serious adverse effects were reported. Minor adverse effects included injection site pain, redness, and swelling.

The New DNA-based Vaccine: GLS-5700
This DNA-based Zika vaccine is the first to demonstrate both safety and the ability to elicit an immune response against Zika in humans, according to new research from the Perelman School of Medicine at the University of Pennsylvania, conducted in partnership with The Wistar Institute, Inovio Pharmaceuticals, and GeneOne Life Science, Inc. In results published today in the New England Journal of Medicine, the phase 1 clinical trial showed for the first time that humans who received up to three doses of the vaccine candidate produced an immune response against Zika with minimal adverse effects, opening the door to further clinical trials for this important vaccine candidate.

The GLS-5700 vaccine is a synthetic DNA vaccine that contains the instructions for the host to mount an immune response against a specific Zika virus antigen.

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Further study is required to fully address the efficacy of this Zika vaccine candidate; however, this study suggests that a DNA vaccine can produce antibodies associated with Zika protection as well as T-cells in a well-tolerated platform, which can be rapidly implemented to target infectious disease.

"Our results show great promise that synthetic DNA vaccines for Zika and other viruses, such as Chikungunya, West Nile Virus, Pandemic Influenza or Ebola, are likely important as viable options for the future of vaccines," Tebas said.

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Reference:

1. Pablo Tebas, M.D., Christine C. Roberts, Ph.D., Kar Muthumani, Ph.D., Emma L. Reuschel, Ph.D., Sagar B. Kudchodkar, Ph.D., Faraz I. Zaidi, M.S., Scott White, M.D., Amir S. Khan, Ph.D., Trina Racine, Ph.D., Hyeree Choi, B.S., Jean Boyer, Ph.D., Young K. Park, J.D., Sylvie Trottier, M.D., Celine Remigio, D.P.T., R.N., Diane Krieger, M.D., Susan E. Spruill, M.S., Mark Bagarazzi, M.D., Gary P. Kobinger, Ph.D., David B. Weiner, Ph.D., and Joel N. Maslow, M.D., Ph.D. 'Safety and Immunogenicity of an Anti–Zika Virus DNA Vaccine - Preliminary Report,' The New England Journal of Medicine; (2017)http://www.nejm.org/doi/full/10.1056/NEJMoa1708120#t=articleMethods

Source-Eurekalert