Zika vaccine shows promise in early human trial
04/10/2017 22:00
By Julie Steenhuysen
CHICAGO, Oct 4 (Reuters) - A DNA-based Zika vaccine from
Inovio Pharmaceuticals Inc INO.O and South Korea's GeneOne
Life Science Inc 011000.KS induced anti-Zika immune responses
in an early stage human trial, U.S. researchers reported on
Wednesday.
Unlike conventional vaccines, which often use inactivated or
killed versions of a virus, the Inovio-GeneOne shot is a
synthetic vaccine made by reproducing sections of the Zika virus
genome in a lab, and then loading them onto a ring of genetic
material called a plasmid.
This vaccine is then injected beneath the skin and followed
up with a device that generates electrical impulses, creating
small pores in cells that allow the DNA to pass into cells.
After three doses of the Zika vaccine known as GLS-5700, all
40 healthy volunteers in the study developed Zika-specific
antibodies.
"Everybody made antibodies," said Dr. Pablo Tebas, an
infectious disease expert at the University of Pennsylvania who
led the study.
To see if these antibodies could be protective against the
virus, blood from immunized study participants was injected into
mice who were then exposed to Zika. Animals that had received
the Zika-specific antibodies were protected.
"When we gave mice serum from the same people before they
got the vaccine, they were not protected. The mice died," Tebas
said in a telephone interview.
Tebas said the study shows how nimble synthetic DNA vaccines
can be, noting that it took just seven months from the time the
vaccine was first designed until the start of the clinical
trial. "This technique of making DNA vaccines is very fast," he
said.
More testing will be needed to show the vaccine is effective
at protecting people from Zika, and that could prove challenging
given that the once explosive epidemic has slowed and there are
few large populations now at risk for Zika infection.
Zika caused thousands of cases of the birth defect known as
microcephaly in Brazil in 2015, prompting the World Health
Organization to declare Zika a public health emergency in
February 2016. Last November, the WHO dropped the emergency
designation, but stressed that the virus, found in at least 60
countries, will keep spreading where mosquitoes that carry the
virus are present.
Last month, Sanofi SA SASY.PA ended development efforts on
its Zika vaccine, based on an inactivated or killed Zika virus.
Takeda Pharmaceutical Co 4502.T is still working on a Zika
vaccine using this approach.
(Reporting by Julie Steenhuysen; Editing by Marguerita Choy)
Keywords: HEALTH ZIKA/VACCINE