Tuesday, August 9, 2016

Three candidate vaccines provide complete protection against the virus Zika in rhesus monkeys

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Three candidate vaccines provide complete protection against the virus Zika in rhesus monkeys -

One month after announcing that two promising vaccine candidates provided mice with complete protection against the virus Zika, a research team at Beth Israel Deaconess Medical Center (BIDMC), in collaboration with scientists from the Institute of Walter Reed Army research (WRAIR) and the University of São Paulo, reports now achieve complete protection against the Zika virus in rhesus monkeys. The research team's findings were published online today in the journal Science.
This week Florida officials have confirmed that fourteen people contracted the virus Zika in Miami-Dade and Broward counties, the first known transmission by mosquitoes in the continental United States. The Centers for Disease Control and Prevention (CDC) has recommended that pregnant women avoid these areas, which is the first time in history that recommended avoiding travel to areas in the continental United States. Because Zika infection among pregnant women has been shown to lead to fetal microcephaly and other major birth defects, development of a safe vaccine is an urgent global health priority.
"Three vaccines provided complete protection against the Zika virus in non-human primates, that is the best animal model before starting clinical trials," said lead author Dan H. Barouch, MD, Ph.D., director of the Center for Virology and Vaccine Research at BIDMC, professor of medicine at Harvard medical School and member of the board at the Ragon Institute of MGH, MIT and Harvard. "The consistent and robust protection against Zika virus in rodents and primates fuels our optimism about the development of a safe and effective vaccine Zika for humans."
Vaccines work by stimulating . the immune system to develop defenses against the virus the researchers tested three means of production Zika immunity in rhesus monkeys: an inactivated virus (PIV) vaccine developed by researchers purified the army to WRAIR and a plasmid DNA vaccine and vector adenovirus-based vaccine product at BIDMC. All three platforms have proven remarkably effective, and no adverse effects were observed.
to test the PIV vaccine, scientists immunized eight monkeys rhesus with inactivated virus Zika and eight monkeys with a dummy vaccine. Within two weeks, the immune system of animals produced antibodies against the virus. After a booster four weeks, the antibody levels increased significantly. When these animals were exposed to two infectious Zika virus strains from Brazil and Puerto Rico, they showed complete protection against the virus, Zika virus without detectable in blood or other bodily secretions.
In a second experiment, 12 rhesus monkeys were immunized with either a DNA vaccine or a vaccine based on adenovirus vectors. These types of vaccines only introduce a DNA fragment Zika virus encoding the outer layer Zika virus in the body. These vaccines have led the immune system to produce antibodies. In this study, both vaccines have produced antibodies specific Zika in all primates tested with the adenoviral-based vaccine causing a wider and a more potent antibody response. When primates were exposed to the Brazilian strain of Zika, both vaccines provide complete protection. These data suggest that clinical trials for these Zika virus vaccine candidates should proceed as quickly as possible.


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