Three-way race to develop vaccine for Zika virus

Trio of vaccines used on monkeys made by scientists from Harvard confer protection

Many athletes and visitors at the Olympic games in Rio may worry about possible contagion with the Zika virus. This concern may soon be a thing of the past as three novel vaccine approaches have been shown to protect monkeys against the virus.

The three vaccine types were made by scientists from Harvard Medical School from the whole, killed virus, from the viral DNA or from a harmless virus used as a transport to bring Zika parts into the body.

All three conferred full protection against infection without any observable adverse effects. The vaccine approaches used in this study appear promising since they were tested in rhesus monkeys, which are very similar to humans. The results were published in the scientific journal Science.

Human trials

“From a scientific perspective, these results are . . . a very promising next step in the process of developing a Zika virus vaccine for use in humans,” says Dr Cillian De Gascun, from the National Virus Reference Laboratory at UCD. “However, until human trials begin, we will not know the efficacy or duration of protection in humans.”


The Zika virus outbreak started last year in South and Central America, expanding rapidly and affecting millions of people.

Infection with the virus usually causes a mild disease with fever and muscle aches. In pregnant women, however, it has been associated with defects in the unborn child, such as microcephaly (an abnormally small head) and neurological disorders. For this study, eight monkeys were treated with a vaccine. Their immune systems were activated and responded to viral components.

The scientists then infected these monkeys and another eight to which they had not given the vaccine. None of the vaccinated monkeys carried virus in their blood following the infection, while all of the untreated monkeys did.