US begins testing of inactivated Zika vaccine in humans

A U.S. military laboratory has recruited 75 healthy adults to commence the first of five early stage clinical trials to test the safety and ability of an investigational Zika purified inactivated vaccine.

Walter Reed Army Institute of Research Clinical Trial Centre in Maryland disclosed this in Maryland, United States of America, on Tuesday.

It said that given the concerns for immune enhancement with other similar flaviviruses like yellow fever and Japanese encephalitis, the vaccine would be tested in some volunteers who would first be vaccinated against one of these other flaviviruses.

The WRAIR said the study was expected to be completed by end of 2018.

It said the vaccine in the trial contains whole Zika virus particles that have been inactivated, meaning that the virus cannot replicate and cause disease in humans.

The WRAIR, however, said the protein shell of the inactivated virus remains intact so it can be recognised by the immune system and evoke an immune response.

It noted that an earlier pre-clinical study found that rhesus monkeys that were vaccinated with the vaccine developed a strong immune response and were protected against two strains of Zika virus.

The WRAIR disclosed that the investigational Zika vaccine would also be included as a part of a U.S. National Institutes of Health trial that began in August.

“The NIH study will test it as a boost vaccination to its DNA Zika vaccine, which entered phase one clinical trials in August.

“That vaccine uses a small, circular piece of DNA, called plasmid, it is injected into the arm muscle to induce an immune response’’, it said.

The WRAIR disclosed further that three other phase one trials to evaluate the new Zika vaccine are scheduled to launch later this year.