(CNN) – Evidence of Zika has been detected in 84 countries across the globe. Some people who contract the disease show no symptoms, but others experience problems with their heart or immune system.

Birth defects linked to Zika include vision and hearing defects, learning disabilities, and in extreme cases, microcephaly, which prevents the head and brain from developing correctly.

As of now, the best option people have for prevention is to wear insect repellent or just avoid being bitten by mosquitoes. However, that may not be the case for much longer.

Researchers are one step closer to developing a vaccine for the Zika virus. The National Institute of Allergy and Infectious Diseases has shown success in early trials of a DNA vaccine candidate and volunteers across the Americas are signing up to help with the next phase.

11 clinics are participating, including locations in Miami, Puerto Rico, Brazil, and Mexico. 90 healthy adults will be divided into groups and receive different doses of the vaccine, testing its safety.

Researchers will then conduct a randomized control trial, using either the vaccine or a placebo, on 24-hundred people who are not infected, but who live in areas where Zika has been transmitted.

The biggest question for researchers now is funding. The trial is fully funded through this phase, but money for the next phase is still up in the air.

The Trump Administration has proposed an 18% cut to the budget of the National Institutes of Health and it is unclear at this point how that cut will affect the trial if approved by congress.