We're just a few weeks away from the Rio Olympics, and Zika is still on many travelers' minds. But finally, there is some good news on the horizon: As of today, two partnering drug companies, Inovio Pharmaceuticals and GeneOne Life Science, have received the necessary FDA approval to start testing an experimental vaccine for the virus in humans, Reuters reports. The companies will enroll 40 healthy participants for this early-stage trial, according to a press release. At this point, the study will just be evaluating the drug (currently called GLS-5700) for safety and whether it causes participants to develop an antibody response. The companies anticipate beginning this trial in the next few weeks and having results from the trial later in the year. If successful, the companies will move on to Phase II testing in participants who actually have the virus. So far, this is one of an estimated 60 groups of companies and researchers working on potential Zika vaccines, according to the World Health Organization (WHO). But even if any of them are successful, the WHO says we're still years away from having a usable vaccine. Still, GLS-5700 is the first potential Zika vaccine to make it to U.S. human trials.