Researchers at Boston's Beth Israel  Deaconess Medical Center have made some promising advances in developing a vaccine to halt the spread of the mosquito-born Zika virus.

Two vaccine candidates—a DNA vaccine, as well as a purified inactivated virus vaccine—both provided complete protection against Zika virus challenge in mice.

 Less than a year after Brazilian officials confirmed the country’s first case in 2015, the World Health Organization declared the virus a public health emergency due to its link to fetal microcephaly. Since then, health officials have made stopping the spread of the Zika virus  a global priority.

Dr. Dan Barouch, Director of the Center for Virology and Vaccine Research at Beth Israelsaid, “Two vaccine candidates—a DNA vaccine, as well as a purified inactivated virus vaccine—both provided complete protection against Zika virus challenge in mice.” 

After vaccination, which only required a single shot, forty-five mice were exposed to Zika after either four or eight weeks. None showed detectable signs of having the virus, while unvaccinated mice showed symptoms similar to reported human cases. 

And though it may be too soon to conclude the vaccine candidates will have equal success in humans, Barouch is confident in the prospect. 

“Based on the robustness of the protection, the demonstration that antibodies protect, and similarities with other related viruses in this family [flaviviruses], for which successful human vaccines have been developed, then our findings certainly raise optimism that the development of a safe and effective vaccine against Zika virus for humans may be successful.” 

With no vaccine currently available, the upcoming Summer Olympics in Rio de Janeiro have been the focus of controversy and fear.  Athletes who may want to have children in the future, such as  the world’s number one golfer Jason Day,  say traveling to Brazil has been a source of anxiety, Many are concerned about the devastating consequences Zika poses to pregnant women. As a result, Day has decided to withdraw from competition. 

Barouch and his colleagues hope that their positive outcomes will advance their vaccines to clinical trials and bring the world “one step closer” to preventing Zika virus. 

But for now, people should continue to take the precautions as advised by local and international health agencies.