An animated picture of zika virus vaccine which is commercially not available in the market right now.

In November 2016, The World Health Organization (WHO) declared that Zika infections are here to stay like yellow fever and malaria, also spread by mosquitoes.

WHO’s statements insist that the fight against the zika virus would take longer than expected as seasonality might return the illness from time to time, and also primarily due to unavailability of cure in the form of vaccines and specialized treatments. Much to the dismay of other public health experts and partners, WHO downgraded the status for Zika infections as “ongoing crisis” from “public health emergency of international concern.”

By October 2016, It was identified that over 70 countries around the globe had reported cases of Zika infections. The scientific community embarked on a challenging journey about this relatively unknown virus that had become a huge health sensation in the last few years and published over 1500 scientific papers after extensive research. The studies confirmed that the virus infects both mothers and unborn children, kill brain cells and causing numerous abnormalities and health concerns such as neural tube defects, eye abnormalities, hearing problems, irritability, seizures and feeding difficulties.

The National Institute of Health’s National Institute of Allergy and Infectious Diseases (NIAID) is currently coordinating all efforts related to the development of most promising Zika vaccine candidates. The research team in the institute had engineered plasmids (circular pieces of DNA) that code for viral proteins. When the DNA vaccine is injected into the muscle, the body cells inherit the ability to make Zika proteins and mount an immune response to the foreign bodies.

The vaccine candidates named VRC5283 and VRC5288 are engineered to prompt cell response to Zika infections by producing the Zika virus structural proteins premembrane (prM) and envelope (E). The scientific merits and discussion related to these vaccine candidates were published in the journal Science on September 22, 2016.

In trials, the research team vaccinated eighteen rhesus monkeys using both Zika DNA vaccines in different doses. The immunity was conferred through two doses over eight weeks. 17 of 18 monkeys examined post exposure of Zika virus showed no detectable virus in their blood.

Now, the scientists have begun their trials on human subjects to test a variety of regimens and doses for safety and immune responses. VRC5288 is currently tested as part of phase 1 trial on volunteers in Maryland and Georgia. VRC5283 is awaiting Phase 1 clinical trial. It is interesting how rapidly the research institute has responded in moving this vaccine from one phase to another.